doc: add CVE-2020-0549 (L1D Eviction Sampling, CacheOut) as unsupported

built from commit ef57f070db
 dated 2026-04-06 03:33:32 +0200
 by Stéphane Lesimple (speed47_github@speed47.net)

.github/workflows/expected_cve_count

@@ -1 +1 @@
-26
+28

README.md

@@ -26,8 +26,10 @@ CVE | Name | Aliases
 [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-2023-20588](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-20588) | AMD Division by Zero Speculative Data Leak | DIV0
 [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-2023-28746](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-28746) | Register File Data Sampling | RFDS
 [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
@@ -60,8 +62,10 @@ CVE-2022-29900 (Retbleed AMD) | 💥 | ✅ | 💥 | ✅ | Kernel update (+ micro
 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-2023-20588 (DIV0) | 💥 | 💥 (1) | 💥 | 💥 (1) | Kernel update (+ disable SMT)
 CVE-2023-20593 (Zenbleed) | 💥 | 💥 | 💥 | 💥 | Microcode update (or kernel workaround)
 CVE-2023-23583 (Reptar) | ☠️ | ☠️ | ☠️ | ☠️ | Microcode update
+CVE-2023-28746 (RFDS) | 💥 | ✅ | 💥 | ✅ | Microcode + kernel 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
@@ -157,6 +161,10 @@ The AVX GATHER instructions can leak data from previously used vector registers
 
 On AMD Zen 1 through Zen 4 processors, an attacker can manipulate the return address predictor to redirect speculative execution on return instructions, leaking kernel memory. Mitigation requires both a kernel update (providing SRSO safe-return sequences or IBPB-on-entry) and a microcode update (providing SBPB on Zen 3/4, or IBPB support on Zen 1/2 — which additionally requires SMT to be disabled). Performance impact ranges from low to significant depending on the chosen mitigation and CPU generation.
 
+**CVE-2023-20588 — AMD Division by Zero Speculative Data Leak (DIV0)**
+
+On AMD Zen 1 processors, a #DE (divide-by-zero) exception can leave stale quotient data from a previous division in the divider unit, observable by a subsequent division via speculative side channels. This can leak data across any privilege boundary, including between SMT sibling threads sharing the same physical core. Mitigation requires a kernel update (Linux 6.5+) that adds a dummy division (`amd_clear_divider()`) on every exit to userspace and before VMRUN, preventing stale data from persisting. No microcode update is needed. Disabling SMT provides additional protection because the kernel mitigation does not cover cross-SMT-thread leaks. Performance impact is negligible.
+
 **CVE-2023-20593 — Cross-Process Information Leak (Zenbleed)**
 
 A bug in AMD Zen 2 processors causes the VZEROUPPER instruction to incorrectly zero register files during speculative execution, leaving stale data from other processes observable in vector registers. This can leak data across any privilege boundary, including from the kernel and other processes, at rates up to 30 KB/s per core. Mitigation is available either through a microcode update that fixes the bug, or through a kernel workaround that sets the FP_BACKUP_FIX bit (bit 9) in the DE_CFG MSR, disabling the faulty optimization. Either approach alone is sufficient. Performance impact is negligible.
@@ -165,6 +173,10 @@ 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-2023-28746 — Register File Data Sampling (RFDS)**
+
+On certain Intel Atom and hybrid processors (Goldmont, Goldmont Plus, Tremont, Gracemont, and the Atom cores of Alder Lake and Raptor Lake), the register file can retain stale data from previous operations that is accessible via speculative execution, allowing an attacker to infer data across privilege boundaries. Mitigation requires both a microcode update (providing the RFDS_CLEAR capability) and a kernel update (CONFIG_MITIGATION_RFDS, Linux 6.9+) that uses the VERW instruction to clear the register file on privilege transitions. CPUs with the RFDS_NO capability bit are not affected. 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.