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7 Commits

Author SHA1 Message Date
Stéphane Lesimple
5af1a9fec9 chore: workflow: add scan id 2026-04-18 16:23:47 +02:00
Stéphane Lesimple
b93027640f chore: vuln workflow: use opus, no persist creds, conditional upload 2026-04-18 16:19:10 +02:00
Stéphane Lesimple
5c27284119 chore: workflow: save logs 2026-04-18 16:05:15 +02:00
Stéphane Lesimple
f2e5999fc0 chore: explicit prompt for workflow 2026-04-18 15:41:03 +02:00
Stéphane Lesimple
25f20b8860 chore: fix workflow perms (#558) 2026-04-18 15:29:54 +02:00
Stéphane Lesimple
77e3dbd6b2 add scheduled vuln research (#557) 2026-04-18 15:14:13 +02:00
Stéphane Lesimple
8a6f9d5d63 Implement ITS/VMScape/BTI and misc enhancements (#539)
7a7408d fix: add rebleet to --variant
cccb3c0 enh: add known fixed ucode versions for CVE-2023-23583 (Reptar) and CVE-2024-45332 (BPI)
090f109 doc: add CVE-2023-31315 (SinkClose) to the unsupported list, add categories
5dc9c3c chore: reorder CVE list in README.md
a00fab1 feat: implement CVE-2025-40300 (VMScape) and CVE-2024-45332 (BTI)
e0b818f chore: stalebot: disable dryrun by default
4af1155 feat: implement CVE-2024-28956 (ITS, Indirect Target Selection) vulnerability and mitigation detection
dfed6f3 doc: add note about more unsupported CVEs
1652977 add a generated version of src/libs/003_intel_models.sh
a089ae8 fix: sys_interface_check() must set the caller's $msg var (closes #533)
cc6bbaa chore: don't include src/ generated files in build
2717b0a doc: CVE-2020-12965 unsupported (#478)
2026-04-04 18:38:49 +02:00
7 changed files with 1894 additions and 253 deletions

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@@ -17,6 +17,8 @@ jobs:
persist-credentials: true
- name: install prerequisites
run: sudo apt-get update && sudo apt-get install -y shellcheck shfmt jq sqlite3 iucode-tool make
- name: update Intel model list
run: ./scripts/update_intel_models.sh
- name: build and check
run: |
make build fmt-check shellcheck
@@ -96,6 +98,7 @@ jobs:
git fetch origin ${{ github.ref_name }}-build
git checkout -f ${{ github.ref_name }}-build
mv $tmpdir/* .
rm -rf src/
mkdir -p .github
rsync -vaP --delete $tmpdir/.github/ .github/
git add --all

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@@ -0,0 +1,199 @@
# Daily transient-execution vulnerability scan
You are a scheduled agent running inside a GitHub Actions job. Your job
is to audit public news/advisory sources for **transient-execution and
CPU side-channel vulnerabilities** that may need to be added to
**spectre-meltdown-checker** (this repository).
## What counts as "relevant"
spectre-meltdown-checker detects, reports, and suggests mitigations for
CPU vulnerabilities such as: Spectre v1/v2/v4, Meltdown, Foreshadow/L1TF,
MDS (ZombieLoad/RIDL/Fallout), TAA, SRBDS, iTLB Multihit, Zenbleed,
Downfall (GDS), Retbleed, Inception, SRSO, BHI, RFDS, Reptar, FP-DSS,
and any similar microarchitectural side-channel or speculative-execution
issue on x86 (Intel/AMD) or ARM CPUs. It also surfaces related hardware
mitigation features (SMAP/SMEP/UMIP/IBPB/eIBRS/STIBP…) when they gate
the remediation for a tracked CVE.
It does **not** track generic software CVEs, GPU driver bugs, networking
stacks, filesystem bugs, userspace crypto issues, or unrelated kernel
subsystems.
## Inputs handed to you by the workflow
- Working directory: the repo root (`/github/workspace` in Actions, or
wherever `actions/checkout` placed it). You may `grep` the repo to
check whether a CVE or codename is already covered.
- `state/seen.json` — memory carried over from the previous run, with
shape:
```json
{
"last_run": "2026-04-17T08:00:12Z",
"seen": {
"<stable-id-1>": { "bucket": "unrelated", "seen_at": "2026-04-17T08:00:12Z", "source": "phoronix" },
"<stable-id-2>": { "bucket": "tocheck", "seen_at": "2026-04-17T08:00:12Z", "source": "oss-sec", "cve": "CVE-2026-1234" }
}
}
```
On the very first run, or when the prior artifact has expired,
the file exists but `seen` is empty and `last_run` is `null`.
- Environment: `SCAN_DATE` (ISO-8601 timestamp of the run start, set by
the workflow). Treat this as "now" for all time-window decisions.
## Time window
This is a belt-and-suspenders design — use **both** mechanisms:
1. **Primary: stable-id dedup.** If an item's stable identifier (see
below) is already present in `state.seen`, skip it entirely — it
was classified on a previous day.
2. **Secondary: 25-hour window.** Among *new* items, prefer those whose
publication/update timestamp is within the last 25 h relative to
`SCAN_DATE`. This bounds work when the prior artifact expired
(90-day retention) or when `last_run` is stale (missed runs).
If `last_run` is older than 25 h, widen the window to
`now - last_run + 1h` so no items are lost across missed runs.
3. Items without a parseable timestamp: include them (fail-safe).
## Sources to poll
Fetch each URL with
`curl -sS -A "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36" -L --max-time 20`.
On non-2xx or timeout, record the failure in the run summary and
continue — do not abort.
### RSS / Atom feeds (primary — parse feed timestamps)
| Short name | URL |
|-----------------|-----|
| phoronix | https://www.phoronix.com/rss.php |
| oss-sec | https://seclists.org/rss/oss-sec.rss |
| lwn | https://lwn.net/headlines/newrss |
| project-zero | https://googleprojectzero.blogspot.com/feeds/posts/default |
| vusec | https://www.vusec.net/feed/ |
| comsec-eth | https://comsec.ethz.ch/category/news/feed/ |
| msrc | https://msrc.microsoft.com/update-guide/rss |
| cisa | https://www.cisa.gov/cybersecurity-advisories/all.xml |
| cert-cc | https://www.kb.cert.org/vuls/atomfeed/ |
### HTML pages (no RSS — fetch, extract dated entries)
| Short name | URL |
|-----------------|-----|
| intel-psirt | https://www.intel.com/content/www/us/en/security-center/default.html |
| amd-psirt | https://www.amd.com/en/resources/product-security.html |
| arm-spec | https://developer.arm.com/Arm%20Security%20Center/Speculative%20Processor%20Vulnerability |
| transient-fail | https://transient.fail/ |
For HTML pages: look for advisory tables or listings with dates. Extract
the advisory title, permalink, and date. If a page has no dates at all,
compare its content against `state.seen` — any new advisory IDs not yet
classified count as "new this run".
## Stable identifier per source
Use the first available of these, in order, as the dedup key:
1. Vendor advisory ID (`INTEL-SA-01234`, `AMD-SB-7001`, `ARM-2024-0042`,
`VU#123456`, `CVE-YYYY-NNNNN`)
2. RSS `<guid>` / Atom `<id>`
3. Permalink URL (`<link>`)
Always also record the permalink URL in the output file so a human can
click through.
## Classification rules
For each **new** item (not in `state.seen`) that passes the time window,
pick exactly one bucket:
- **toimplement** — a clearly-identified new transient-execution / CPU
side-channel vulnerability in scope, **and not already covered by
this repo**. Verify the second half by grepping the repo for the CVE
ID *and* the codename before classifying; if either matches existing
code, demote to `tocheck`.
- **tocheck** — plausibly in-scope but ambiguous: mitigation-only
feature (LASS, IBT, APIC-virt, etc.); item seemingly already
implemented but worth confirming scope; unclear applicability
(e.g. embedded-only ARM SKU); CVE-ID pending; contradictory info
across sources. State clearly what would resolve the ambiguity.
- **unrelated** — everything else.
Tie-breakers: prefer `tocheck` over `unrelated` when uncertain. Prefer
`tocheck` over `toimplement` when the CVE ID is still "reserved" /
"pending" — false positives in `toimplement` waste human time more than
false positives in `tocheck`.
## Outputs
Compute `TODAY=$(date -u -d "$SCAN_DATE" +%F)`. Write these files under
the repo root, overwriting if they already exist (they shouldn't unless
the workflow re-ran the same day):
- `rss_${TODAY}_toimplement.md`
- `rss_${TODAY}_tocheck.md`
- `rss_${TODAY}_unrelated.md`
Each file uses level-2 headers per source short-name, then one bullet
per item: the stable ID (if any), the permalink URL, and 12 sentences.
Keep entries terse — a human skims these daily.
```markdown
## oss-sec
- **CVE-2026-1234** — https://www.openwall.com/lists/oss-security/2026/04/18/3
New Intel transient-execution bug "Foo" disclosed today; affects
Redwood Cove cores, microcode fix pending. Not yet covered by this
repo (grepped for CVE-2026-1234 and "Foo" — no matches).
## phoronix
- https://www.phoronix.com/news/Some-Article
Linux 7.2 drops a compiler-target flag; unrelated to CPU side channels.
```
If a bucket has no items, write the file with a single line
`(no new items in this window)` so it is obvious the job ran.
### Run summary
Append this block to the **tocheck** file (creating it if empty):
```markdown
## Run summary
- SCAN_DATE: <value>
- window cutoff: <computed cutoff>
- prior state size: <N> entries, last_run=<value>
- per-source new item counts: phoronix=<n>, oss-sec=<n>, lwn=<n>, ...
- fetch failures: <list, or "none">
- total classified this run: toimplement=<n>, tocheck=<n>, unrelated=<n>
```
### State update
Rewrite `state/seen.json` with:
- `last_run` = `SCAN_DATE`
- `seen` = union of (pruned prior `seen`) (all items classified this
run, keyed by stable ID, with `{bucket, seen_at=SCAN_DATE, source, cve?}`)
Pruning (keep state bounded): drop any entry whose `seen_at` is older
than 30 days before `SCAN_DATE`. The workflow step also does this as
a safety net, but do it here too so the in-memory view is consistent.
## Guardrails
- Do NOT modify any repo source code. Only write the three markdown
output files and `state/seen.json`.
- Do NOT create commits, branches, or PRs.
- Do NOT call any tool that posts externally (Slack, GitHub comments,
issues, email, etc.).
- Do NOT follow links off-site for deeper investigation unless strictly
needed to resolve a `tocheck` ambiguity — budget of at most 5 such
follow-ups per run.
- If a source returns unexpectedly large content, truncate to the first
~200 items before parsing.
- If total runtime exceeds 15 minutes, finish whatever you can,
write partial outputs, and note it in the run summary.

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@@ -1 +1 @@
21
26

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@@ -30,4 +30,4 @@ jobs:
days-before-close: 7
stale-issue-label: stale
remove-stale-when-updated: true
debug-only: ${{ case(inputs.action == 'apply', false, true) }}
debug-only: ${{ case(inputs.action == 'dryrun', true, false) }}

129
.github/workflows/vuln-scan.yml vendored Normal file
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@@ -0,0 +1,129 @@
name: Online search for vulns
on:
schedule:
- cron: '42 8 * * *'
workflow_dispatch: {} # allow manual trigger
permissions:
contents: read
actions: read # needed to list/download previous run artifacts
id-token: write # needed to mint OIDC token
concurrency:
group: vuln-scan
cancel-in-progress: true
jobs:
scan:
runs-on: ubuntu-latest
timeout-minutes: 20
steps:
- name: Checkout repository (for grep-based dedup against existing checks)
uses: actions/checkout@v5
with:
fetch-depth: 1
persist-credentials: false
# ---- Load previous state ---------------------------------------------
# Find the most recent successful run of THIS workflow (other than the
# current one) and pull its `vuln-scan-state` artifact. On the very
# first run there will be none — that's fine, we start empty.
- name: Find previous successful run id
id: prev
env:
GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
run: |
set -e
run_id=$(gh run list \
--workflow="${{ github.workflow }}" \
--status=success \
--limit 1 \
--json databaseId \
--jq '.[0].databaseId // empty')
echo "run_id=${run_id}" >> "$GITHUB_OUTPUT"
if [ -n "$run_id" ]; then
echo "Found previous successful run: $run_id"
else
echo "No previous successful run — starting from empty state."
fi
- name: Download previous state artifact
if: steps.prev.outputs.run_id != ''
uses: actions/download-artifact@v4
continue-on-error: true # tolerate retention expiry
with:
name: vuln-scan-state
path: state/
run-id: ${{ steps.prev.outputs.run_id }}
github-token: ${{ secrets.GITHUB_TOKEN }}
- name: Ensure state file exists
run: |
mkdir -p state
if [ ! -f state/seen.json ]; then
echo '{"last_run": null, "seen": {}}' > state/seen.json
echo "Initialized empty state."
fi
echo "State size: $(wc -c < state/seen.json) bytes"
# ---- Run the scan ----------------------------------------------------
# Runs Claude Code against daily_vuln_scan_prompt.md.
# That prompt file fully specifies: sources to poll, how to read
# state/seen.json, the 25-hour window, the output files to write,
# and how to rewrite state/seen.json at the end of the run.
- name: Research for online mentions of new vulns
id: scan
uses: anthropics/claude-code-action@v1
env:
SCAN_DATE: ${{ github.run_started_at }}
with:
claude_args: |
--model claude-opus-4-7 --allowedTools "Read,Write,Edit,Bash,Grep,Glob,WebFetch"
prompt: |
Read the full task instructions from .github/workflows/daily_vuln_scan_prompt.md and execute them end-to-end. That file fully specifies: sources to poll, how to read and update state/seen.json, the 25-hour window, which rss_YYYY-MM-DD_*.md files to write, and the run guardrails. Use $SCAN_DATE (env var) as "now" for time-window decisions.
claude_code_oauth_token: ${{ secrets.CLAUDE_CODE_OAUTH_TOKEN }}
- name: Upload Claude execution log
if: ${{ always() && steps.scan.outputs.execution_file != '' }}
uses: actions/upload-artifact@v4
with:
name: claude-execution-log-${{ github.run_id }}
path: ${{ steps.scan.outputs.execution_file }}
retention-days: 30
if-no-files-found: warn
# ---- Persist outputs -------------------------------------------------
- name: Prune state (keep only entries from the last 30 days)
run: |
python3 - <<'PY'
import json, datetime, pathlib
p = pathlib.Path("state/seen.json")
data = json.loads(p.read_text())
cutoff = (datetime.datetime.utcnow() - datetime.timedelta(days=30)).isoformat()
before = len(data.get("seen", {}))
data["seen"] = {
k: v for k, v in data.get("seen", {}).items()
if v.get("seen_at", "9999") >= cutoff
}
after = len(data["seen"])
p.write_text(json.dumps(data, indent=2, sort_keys=True))
print(f"Pruned state: {before} -> {after} entries")
PY
- name: Upload new state artifact
uses: actions/upload-artifact@v4
with:
name: vuln-scan-state
path: state/seen.json
retention-days: 90
if-no-files-found: error
- name: Upload daily report
uses: actions/upload-artifact@v4
with:
name: vuln-scan-report-${{ github.run_id }}
path: rss_*.md
retention-days: 90
if-no-files-found: warn

View File

@@ -16,18 +16,23 @@ CVE | Name | Aliases
[CVE-2018-3620](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-3620) | L1 Terminal Fault | Foreshadow-NG (OS/SMM)
[CVE-2018-3646](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-3646) | L1 Terminal Fault | Foreshadow-NG (VMM)
[CVE-2018-12126](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-12126) | Microarchitectural Store Buffer Data Sampling | MSBDS, Fallout
[CVE-2018-12130](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-12130) | Microarchitectural Fill Buffer Data Sampling | MFBDS, ZombieLoad
[CVE-2018-12127](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-12127) | Microarchitectural Load Port Data Sampling | MLPDS, RIDL
[CVE-2018-12130](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-12130) | Microarchitectural Fill Buffer Data Sampling | MFBDS, ZombieLoad
[CVE-2018-12207](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-12207) | Machine Check Exception on Page Size Changes | iTLB Multihit, No eXcuses
[CVE-2019-11091](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-11091) | Microarchitectural Data Sampling Uncacheable Memory | MDSUM, RIDL
[CVE-2019-11135](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-11135) | TSX Asynchronous Abort | TAA, ZombieLoad V2
[CVE-2018-12207](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-12207) | Machine Check Exception on Page Size Changes | iTLB Multihit, No eXcuses
[CVE-2020-0543](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-0543) | Special Register Buffer Data Sampling | SRBDS, CROSSTalk
[CVE-2022-29900](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-29900) | Arbitrary Speculative Code Execution with Return Instructions | Retbleed (AMD)
[CVE-2022-29901](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-29901) | Arbitrary Speculative Code Execution with Return Instructions | Retbleed (Intel), RSBA
[CVE-2022-40982](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-40982) | Gather Data Sampling | Downfall, GDS
[CVE-2023-20569](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-20569) | Return Address Security | Inception, SRSO
[CVE-2023-20593](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-20593) | Cross-Process Information Leak | Zenbleed
[CVE-2023-23583](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-23583) | Redundant Prefix Issue | Reptar
[CVE-2024-28956](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-28956) | Indirect Target Selection | ITS
[CVE-2024-36350](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-36350) | Transient Scheduler Attack, Store Queue | TSA-SQ
[CVE-2024-36357](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-36357) | Transient Scheduler Attack, L1 | TSA-L1
[CVE-2025-40300](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2025-40300) | VM-Exit Stale Branch Prediction | VMScape
[CVE-2024-45332](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-45332) | Branch Privilege Injection | BPI
## Am I at risk?
@@ -45,18 +50,23 @@ CVE-2018-3615 (Foreshadow, SGX) | ✅ (3) | ✅ (3) | ✅ (3) | ✅ (3) | Microc
CVE-2018-3620 (Foreshadow-NG, OS/SMM) | 💥 | ✅ | ✅ | ✅ | Kernel update
CVE-2018-3646 (Foreshadow-NG, VMM) | ✅ | ✅ | 💥 | 💥 | Kernel update (or disable EPT/SMT)
CVE-2018-12126 (MSBDS, Fallout) | 💥 | 💥 (1) | 💥 | 💥 (1) | Microcode + kernel update
CVE-2018-12130 (MFBDS, ZombieLoad) | 💥 | 💥 (1) | 💥 | 💥 (1) | Microcode + kernel update
CVE-2018-12127 (MLPDS, RIDL) | 💥 | 💥 (1) | 💥 | 💥 (1) | Microcode + kernel update
CVE-2018-12130 (MFBDS, ZombieLoad) | 💥 | 💥 (1) | 💥 | 💥 (1) | Microcode + kernel update
CVE-2018-12207 (iTLB Multihit, No eXcuses) | ✅ | ✅ | ☠️ | ✅ | Hypervisor update (or disable hugepages)
CVE-2019-11091 (MDSUM, RIDL) | 💥 | 💥 (1) | 💥 | 💥 (1) | Microcode + kernel update
CVE-2019-11135 (TAA, ZombieLoad V2) | 💥 | 💥 (1) | 💥 | 💥 (1) | Microcode + kernel update
CVE-2018-12207 (iTLB Multihit, No eXcuses) | ✅ | ✅ | ☠️ | ✅ | Hypervisor update (or disable hugepages)
CVE-2020-0543 (SRBDS, CROSSTalk) | 💥 (2) | 💥 (2) | 💥 (2) | 💥 (2) | Microcode + kernel update
CVE-2022-29900 (Retbleed AMD) | 💥 | ✅ | 💥 | ✅ | Kernel update (+ microcode for IBPB)
CVE-2022-29901 (Retbleed Intel, RSBA) | 💥 | ✅ | 💥 | ✅ | Microcode + kernel update (eIBRS or IBRS)
CVE-2022-40982 (Downfall, GDS) | 💥 | 💥 | 💥 | 💥 | Microcode update (or disable AVX)
CVE-2023-20569 (Inception, SRSO) | 💥 | ✅ | 💥 | ✅ | Microcode + kernel update
CVE-2023-20593 (Zenbleed) | 💥 | 💥 | 💥 | 💥 | Microcode update (or kernel workaround)
CVE-2023-23583 (Reptar) | ☠️ | ☠️ | ☠️ | ☠️ | Microcode update
CVE-2024-28956 (ITS) | 💥 | ✅ | 💥 (4) | ✅ | Microcode + kernel update
CVE-2024-36350 (TSA-SQ) | 💥 | 💥 (1) | 💥 | 💥 (1) | Microcode + kernel update
CVE-2024-36357 (TSA-L1) | 💥 | 💥 (1) | 💥 | 💥 (1) | Microcode + kernel update
CVE-2025-40300 (VMScape) | ✅ | ✅ | 💥 | ✅ | Kernel update (IBPB on VM-exit)
CVE-2024-45332 (BPI) | 💥 | ✅ | 💥 | ✅ | Microcode update
> 💥 Data can be leaked across this boundary.
@@ -70,6 +80,8 @@ CVE-2024-36357 (TSA-L1) | 💥 | 💥 (1) | 💥 | 💥 (1) | Microcode + kernel
> (3) CVE-2018-3615 (Foreshadow SGX) inverts the normal trust model: the OS reads SGX enclave data. It is irrelevant unless the system runs SGX enclaves, and the attacker must already have OS-level access.
> (4) VM→Host leakage applies only to certain affected CPU models (Skylake-X, Kaby Lake, Comet Lake). Ice Lake, Tiger Lake, and Rocket Lake are only affected for native (user-to-kernel) attacks, not guest-to-host.
## Detailed CVE descriptions
<details>
@@ -109,26 +121,34 @@ A guest VM can exploit L1TF to read memory belonging to the host or other guests
**CVE-2018-12126 — Microarchitectural Store Buffer Data Sampling (MSBDS, Fallout)**
**CVE-2018-12130 — Microarchitectural Fill Buffer Data Sampling (MFBDS, ZombieLoad)**
**CVE-2018-12127 — Microarchitectural Load Port Data Sampling (MLPDS, RIDL)**
**CVE-2018-12130 — Microarchitectural Fill Buffer Data Sampling (MFBDS, ZombieLoad)**
**CVE-2019-11091 — Microarchitectural Data Sampling Uncacheable Memory (MDSUM, RIDL)**
These four CVEs are collectively known as "MDS" (Microarchitectural Data Sampling) vulnerabilities. They exploit different CPU internal buffers — store buffer, fill buffer, load ports, and uncacheable memory paths — that can leak recently accessed data across privilege boundaries during speculative execution. An unprivileged attacker can observe data recently processed by the kernel or other processes. Mitigation requires a microcode update (providing the MD_CLEAR mechanism) plus a kernel update that uses VERW to clear affected buffers on privilege transitions. Disabling Hyper-Threading (SMT) provides additional protection because sibling threads share these buffers. The performance impact is low to significant, depending on the frequency of kernel transitions and whether SMT is disabled.
**CVE-2019-11135 — TSX Asynchronous Abort (TAA, ZombieLoad V2)**
On CPUs with Intel TSX, a transactional abort can leave data from the line fill buffers in a state observable through side channels, similar to the MDS vulnerabilities but triggered through TSX. Mitigation requires a microcode update plus kernel support to either clear affected buffers or disable TSX entirely (via the TSX_CTRL MSR). The performance impact is low to significant, similar to MDS, with the option to eliminate the attack surface entirely by disabling TSX at the cost of losing transactional memory support.
**CVE-2018-12207 — Machine Check Exception on Page Size Changes (iTLB Multihit, No eXcuses)**
A malicious guest VM can trigger a machine check exception (MCE) — crashing the entire host — by creating specific conditions in the instruction TLB involving page size changes. This is a denial-of-service vulnerability affecting hypervisors running untrusted guests. Mitigation requires either disabling hugepage use in the hypervisor or updating the hypervisor to avoid the problematic iTLB configurations. The performance impact ranges from low to significant depending on the approach: disabling hugepages can substantially impact memory-intensive workloads.
**CVE-2019-11135 — TSX Asynchronous Abort (TAA, ZombieLoad V2)**
On CPUs with Intel TSX, a transactional abort can leave data from the line fill buffers in a state observable through side channels, similar to the MDS vulnerabilities but triggered through TSX. Mitigation requires a microcode update plus kernel support to either clear affected buffers or disable TSX entirely (via the TSX_CTRL MSR). The performance impact is low to significant, similar to MDS, with the option to eliminate the attack surface entirely by disabling TSX at the cost of losing transactional memory support.
**CVE-2020-0543 — Special Register Buffer Data Sampling (SRBDS, CROSSTalk)**
Certain special CPU instructions (RDRAND, RDSEED, EGETKEY) read data through a shared staging buffer that is accessible across all cores via speculative execution. An attacker running code on any core can observe the output of these instructions from a victim on a different core, including extracting cryptographic keys from SGX enclaves (a complete ECDSA key was demonstrated). This is notable as one of the first cross-core speculative execution attacks. Mitigation requires a microcode update that serializes access to the staging buffer, plus a kernel update to manage the mitigation. Performance impact is low, mainly affecting workloads that heavily use RDRAND/RDSEED.
**CVE-2022-29900 — Arbitrary Speculative Code Execution with Return Instructions (Retbleed AMD)**
On AMD processors from families 0x15 through 0x17 (Bulldozer through Zen 2) and Hygon family 0x18, an attacker can exploit return instructions to redirect speculative execution and leak kernel memory, bypassing retpoline mitigations that were effective against Spectre V2. Unlike Spectre V2 which targets indirect jumps and calls, Retbleed specifically targets return instructions, which were previously considered safe. Mitigation requires a kernel update providing either the untrained return thunk (safe RET) or IBPB-on-entry mechanism, plus a microcode update providing IBPB support on Zen 1/2. On Zen 1/2, SMT should be disabled for full protection when using IBPB-based mitigation. Performance impact is medium.
**CVE-2022-29901 — Arbitrary Speculative Code Execution with Return Instructions (Retbleed Intel, RSBA)**
On Intel Skylake through Rocket Lake processors with RSB Alternate Behavior (RSBA), return instructions can be speculatively redirected via the Branch Target Buffer when the Return Stack Buffer underflows, bypassing retpoline mitigations. Mitigation requires either Enhanced IBRS (eIBRS, via microcode update) or a kernel compiled with IBRS-on-entry support (Linux 5.19+). Call depth tracking (stuffing) is an alternative mitigation available from Linux 6.2+. Plain retpoline does NOT mitigate this vulnerability on RSBA-capable CPUs. Performance impact is medium to high.
**CVE-2022-40982 — Gather Data Sampling (GDS, Downfall)**
The AVX GATHER instructions can leak data from previously used vector registers across privilege boundaries through the shared gather data buffer. This affects any software using AVX2 or AVX-512 on vulnerable Intel processors. Mitigation is provided by a microcode update that clears the gather buffer, or alternatively by disabling the AVX feature entirely. Performance impact is negligible for most workloads but can be significant (up to 50%) for AVX-heavy applications such as HPC and AI inference.
@@ -145,6 +165,10 @@ A bug in AMD Zen 2 processors causes the VZEROUPPER instruction to incorrectly z
A bug in Intel processors causes unexpected behavior when executing instructions with specific redundant REX prefixes. Depending on the circumstances, this can result in a system crash (MCE), unpredictable behavior, or potentially privilege escalation. Any software running on an affected CPU can trigger the bug. Mitigation requires a microcode update. Performance impact is low.
**CVE-2024-28956 — Indirect Target Selection (ITS)**
On certain Intel processors (Skylake-X stepping 6+, Kaby Lake, Comet Lake, Ice Lake, Tiger Lake, Rocket Lake), an attacker can train the indirect branch predictor to speculatively execute a targeted gadget in the kernel, bypassing eIBRS protections. The Branch Target Buffer (BTB) uses only partial address bits to index indirect branch targets, allowing user-space code to influence kernel-space speculative execution. Some affected CPUs (Ice Lake, Tiger Lake, Rocket Lake) are only vulnerable to native user-to-kernel attacks, not guest-to-host (VMX) attacks. Mitigation requires both a microcode update (IPU 2025.1 / microcode-20250512+, which fixes IBPB to fully flush indirect branch predictions) and a kernel update (CONFIG_MITIGATION_ITS, Linux 6.15+) that aligns branch/return thunks or uses RSB stuffing. Performance impact is low.
**CVE-2024-36350 — Transient Scheduler Attack, Store Queue (TSA-SQ)**
On AMD Zen 3 and Zen 4 processors, the CPU's transient scheduler may speculatively retrieve stale data from the store queue during certain timing windows, allowing an attacker to infer data from previous store operations across privilege boundaries. The attack can also leak data between SMT sibling threads. Mitigation requires both a microcode update (exposing the VERW_CLEAR capability) and a kernel update (CONFIG_MITIGATION_TSA, Linux 6.16+) that uses the VERW instruction to clear CPU buffers on user/kernel transitions and before VMRUN. The kernel also clears buffers on idle when SMT is active. Performance impact is low to medium.
@@ -153,8 +177,23 @@ On AMD Zen 3 and Zen 4 processors, the CPU's transient scheduler may speculative
On AMD Zen 3 and Zen 4 processors, the CPU's transient scheduler may speculatively retrieve stale data from the L1 data cache during certain timing windows, allowing an attacker to infer data in the L1D cache across privilege boundaries. Mitigation requires the same microcode and kernel updates as TSA-SQ: a microcode update exposing VERW_CLEAR and a kernel update (CONFIG_MITIGATION_TSA, Linux 6.16+) that clears CPU buffers via VERW on privilege transitions. Performance impact is low to medium.
**CVE-2025-40300 — VM-Exit Stale Branch Prediction (VMScape)**
After a guest VM exits to the host, stale branch predictions from the guest can influence host-side speculative execution before the kernel returns to userspace, allowing a local attacker to leak host kernel memory. This affects Intel processors from Sandy Bridge through Arrow Lake/Lunar Lake, AMD Zen 1 through Zen 5 families, and Hygon family 0x18. Only systems running a hypervisor with untrusted guests are at risk. Mitigation requires a kernel update (CONFIG_MITIGATION_VMSCAPE, Linux 6.18+) that issues IBPB before returning to userspace after a VM exit. No specific microcode update is required beyond existing IBPB support. Performance impact is low.
**CVE-2024-45332 — Branch Privilege Injection (BPI)**
A race condition in the branch predictor update mechanism of Intel processors (Coffee Lake through Raptor Lake, plus some server and Atom parts) allows user-space branch predictions to briefly influence kernel-space speculative execution, undermining eIBRS and IBPB protections. This means systems relying solely on eIBRS for Spectre V2 mitigation may not be fully protected without the microcode fix. Mitigation requires a microcode update (intel-microcode 20250512+) that fixes the asynchronous branch predictor update timing so that eIBRS and IBPB work as originally intended. No kernel changes are required. Performance impact is negligible.
</details>
## Unsupported CVEs
Several transient execution CVEs are not covered by this tool, for various reasons (duplicates, only
affecting non-supported hardware or OS, theoretical with no known exploitation, etc.).
The complete list along with the reason for each exclusion is available in the
[UNSUPPORTED_CVE_LIST.md](https://github.com/speed47/spectre-meltdown-checker/blob/source/UNSUPPORTED_CVE_LIST.md) file.
## Scope
Supported operating systems:

File diff suppressed because it is too large Load Diff