diff --git a/README.md b/README.md
index 4a9c718..e139f18 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,16 @@
 Spectre & Meltdown Checker
 ==========================
 
-A shell script to tell if your system is vulnerable against the 3 "speculative execution" CVEs that were made public early 2018.
+A shell script to tell if your system is vulnerable against the several "speculative execution" CVEs that were made public in 2018.
+
+This includes:
+- CVE-2017-5753 aka Spectre Variant 1
+- CVE-2017-5715 aka Spectre Variant 2
+- CVE-2017-5754 aka Meltdown or Variant 3
+- CVE-2018-3640 aka Variant 3a
+- CVE-2018-3639 aka Variant 4
+
+**Note: as CVE-2018-3639 and CVE-2018-3640 are extremely recent (published on May 21th 2018), expect frequent changes of the script in the next days to adjust detection.**
 
 Supported operating systems:
 - Linux (all versions, flavors and distros)
@@ -74,7 +83,19 @@ sudo ./spectre-meltdown-checker.sh
    - Mitigation: updated kernel (with PTI/KPTI patches), updating the kernel is enough
    - Performance impact of the mitigation: low to medium
 
-## Disclaimer
+**CVE-2018-3640** rogue system register read (Variant 3a)
+
+   - Impact: TBC
+   - Mitigation: TBC
+   - Performance impact of the mitigation: negligible
+
+**CVE-2018-3639** speculative store bypass (Variant 4)
+
+   - Impact: software using JIT (no known exploitation against kernel)
+   - Mitigation: TBC
+   - Performance impact of the mitigation: low to medium
+
+## Understanding what this script does and doesn't
 
 This tool does its best to determine whether your system is immune (or has proper mitigations in place) for the collectively named "speculative execution" vulnerabilities. It doesn't attempt to run any kind of exploit, and can't guarantee that your system is secure, but rather helps you verifying whether your system has the known correct mitigations in place.
 However, some mitigations could also exist in your kernel that this script doesn't know (yet) how to detect, or it might falsely detect mitigations that in the end don't work as expected (for example, on backported or modified kernels).
diff --git a/spectre-meltdown-checker.sh b/spectre-meltdown-checker.sh
index efa4812..062eec8 100755
--- a/spectre-meltdown-checker.sh
+++ b/spectre-meltdown-checker.sh
@@ -243,18 +243,22 @@ is_cpu_vulnerable_cached=0
 _is_cpu_vulnerable_cached()
 {
 	# shellcheck disable=SC2086
-	[ "$1" = 1 ] && return $variant1
+	[ "$1" = 1  ] && return $variant1
 	# shellcheck disable=SC2086
-	[ "$1" = 2 ] && return $variant2
+	[ "$1" = 2  ] && return $variant2
 	# shellcheck disable=SC2086
-	[ "$1" = 3 ] && return $variant3
+	[ "$1" = 3  ] && return $variant3
+	# shellcheck disable=SC2086
+	[ "$1" = 3a ] && return $variant3a
+	# shellcheck disable=SC2086
+	[ "$1" = 4  ] && return $variant4
 	echo "$0: error: invalid variant '$1' passed to is_cpu_vulnerable()" >&2
 	exit 255
 }
 
 is_cpu_vulnerable()
 {
-	# param: 1, 2 or 3 (variant)
+	# param: 1, 2, 3, 3a or 4 (variant)
 	# returns 0 if vulnerable, 1 if not vulnerable
 	# (note that in shell, a return of 0 is success)
 	# by default, everything is vulnerable, we work in a "whitelist" logic here.
@@ -267,11 +271,15 @@ is_cpu_vulnerable()
 	variant1=''
 	variant2=''
 	variant3=''
+	variant3a=''
+	variant4=''
 
 	if is_cpu_specex_free; then
 		variant1=immune
 		variant2=immune
 		variant3=immune
+		variant3a=immune
+		variant4=immune
 	elif is_intel; then
 		# Intel
 		# https://github.com/crozone/SpectrePoC/issues/1 ^F E5200 => spectre 2 not vulnerable
@@ -343,16 +351,29 @@ is_cpu_vulnerable()
 					_debug "checking cpu$i: this arm non vulnerable to meltdown"
 					[ -z "$variant3" ] && variant3=immune
 				fi
+
+				# for variant3a, only A15/A57/A72 are vulnerable
+				if [ "$cpuarch" = 8 ] && echo "$cpupart" | grep -Eq '^0x(c0f|d07|d0a)$'; then
+					_debug "checking cpu$i: arm A15-A57-A72 vulnerable to variant3a"
+					variant3a=vuln
+				else
+					_debug "checking cpu$i: this arm non vulnerable to variant3a"
+					[ -z "$variant3" ] && variant3a=immune
+				fi
 			fi
-			_debug "is_cpu_vulnerable: for cpu$i and so far, we have <$variant1> <$variant2> <$variant3>"
+			_debug "is_cpu_vulnerable: for cpu$i and so far, we have <$variant1> <$variant2> <$variant3> <$variant3a> <$variant4>"
 		done
 	fi
-	_debug "is_cpu_vulnerable: temp results are <$variant1> <$variant2> <$variant3>"
+	# from the information we have for now, it seems that CPUs that are vulnerable to variant1 are also vulnerable to variant4
+	variant4=$variant1
+	_debug "is_cpu_vulnerable: temp results are <$variant1> <$variant2> <$variant3> <$variant3a> <$variant4>"
 	# if at least one of the cpu is vulnerable, then the system is vulnerable
-	[ "$variant1" = "immune" ] && variant1=1 || variant1=0
-	[ "$variant2" = "immune" ] && variant2=1 || variant2=0
-	[ "$variant3" = "immune" ] && variant3=1 || variant3=0
-	_debug "is_cpu_vulnerable: final results are <$variant1> <$variant2> <$variant3>"
+	[ "$variant1"  = "immune" ] && variant1=1  || variant1=0
+	[ "$variant2"  = "immune" ] && variant2=1  || variant2=0
+	[ "$variant3"  = "immune" ] && variant3=1  || variant3=0
+	[ "$variant3a" = "immune" ] && variant3a=1 || variant3a=0
+	[ "$variant4"  = "immune" ] && variant4=1  || variant4=0
+	_debug "is_cpu_vulnerable: final results are <$variant1> <$variant2> <$variant3> <$variant3a> <$variant4>"
 	is_cpu_vulnerable_cached=1
 	_is_cpu_vulnerable_cached "$1"
 	return $?
@@ -496,11 +517,13 @@ while [ -n "$1" ]; do
 			exit 255
 		fi
 		case "$2" in
-			1) opt_variant1=1; opt_allvariants=0;;
-			2) opt_variant2=1; opt_allvariants=0;;
-			3) opt_variant3=1; opt_allvariants=0;;
+			1)  opt_variant1=1;  opt_allvariants=0;;
+			2)  opt_variant2=1;  opt_allvariants=0;;
+			3)  opt_variant3=1;  opt_allvariants=0;;
+			3a) opt_variant3a=1; opt_allvariants=0;;
+			4)  opt_variant4=1;  opt_allvariants=0;;
 			*)
-				echo "$0: error: invalid parameter '$2' for --variant, expected either 1, 2 or 3" >&2;
+				echo "$0: error: invalid parameter '$2' for --variant, expected either 1, 2, 3, 3a or 4" >&2;
 				exit 255
 				;;
 		esac
@@ -567,6 +590,8 @@ pvulnstatus()
 			CVE-2017-5753) aka="SPECTRE VARIANT 1";;
 			CVE-2017-5715) aka="SPECTRE VARIANT 2";;
 			CVE-2017-5754) aka="MELTDOWN";;
+			CVE-2018-3640) aka="VARIANT 3A";;
+			CVE-2018-3639) aka="VARIANT 4";;
 		esac
 
 		case "$opt_batch_format" in
@@ -888,6 +913,7 @@ parse_cpu_details()
 	# get raw cpuid, it's always useful (referenced in the Intel doc for firmware updates for example)
 	if read_cpuid 0x1 $EAX 0 0xFFFFFFFF; then
 		cpuid="$read_cpuid_value"
+		#cpuid_hex=$(printf "%X" "$cpuid")
 	fi
 
 	# under BSD, linprocfs often doesn't export ucode information, so fetch it ourselves the good old way
@@ -1411,7 +1437,6 @@ read_msr()
 	return 0
 }
 
-
 check_cpu()
 {
 	_info "\033[1;34mHardware check\033[0m"
@@ -1627,6 +1652,19 @@ check_cpu()
 		fi
 	fi
 
+	# variant 4
+	_info     "  * Speculative Store Bypass Disable (SSBD)"
+	_info_nol "    * CPU indicates SSBD capability: "
+	read_cpuid 0x7 $EDX 31 1 1; ret=$?
+	if [ $ret -eq 0 ]; then
+		#cpuid_ng1=1
+		pstatus green YES "SSBD feature bit"
+	elif [ $ret -eq 1 ]; then
+		pstatus yellow NO
+	else
+		pstatus yellow UNKNOWN "is cpuid kernel module available?"
+	fi
+
 	if is_intel; then
 		_info     "  * Enhanced IBRS (IBRS_ALL)"
 		_info_nol "    * CPU indicates ARCH_CAPABILITIES MSR availability: "
@@ -1680,11 +1718,13 @@ check_cpu()
 			capabilities=$val_cap_msr
 			capabilities_rdcl_no=0
 			capabilities_ibrs_all=0
+			capabilities_ssb_no=0
 			if [ $val -eq 0 ]; then
 				_debug "capabilities MSR lower byte is $capabilities (decimal)"
-				[ $(( capabilities & 1 )) -eq 1 ] && capabilities_rdcl_no=1
-				[ $(( capabilities & 2 )) -eq 2 ] && capabilities_ibrs_all=1
-				_debug "capabilities says rdcl_no=$capabilities_rdcl_no ibrs_all=$capabilities_ibrs_all"
+				[ $(( capabilities &  1 )) -eq 1  ] && capabilities_rdcl_no=1
+				[ $(( capabilities &  2 )) -eq 2  ] && capabilities_ibrs_all=1
+				[ $(( capabilities & 16 )) -eq 16 ] && capabilities_ssb_no=1
+				_debug "capabilities says rdcl_no=$capabilities_rdcl_no ibrs_all=$capabilities_ibrs_all ssb_no=$capabilities_ssb_no"
 				if [ "$capabilities_ibrs_all" = 1 ]; then
 					if [ $cpu_mismatch -eq 0 ]; then
 						pstatus green YES
@@ -1709,6 +1749,15 @@ check_cpu()
 		else
 			pstatus yellow NO
 		fi
+
+		_info_nol "  * CPU explicitly indicates not being vulnerable to Variant 4 (SSB_NO): "
+		if [ "$capabilities_ssb_no" = -1 ]; then
+			pstatus yellow UNKNOWN
+		elif [ "$capabilities_ssb_no" = 1 ]; then
+			pstatus green YES
+		else
+			pstatus yellow NO
+		fi
 	fi
 
 	_info_nol "  * CPU microcode is known to cause stability problems: "
@@ -1727,8 +1776,8 @@ check_cpu()
 
 check_cpu_vulnerabilities()
 {
-	_info     "* CPU vulnerability to the three speculative execution attack variants"
-	for v in 1 2 3; do
+	_info     "* CPU vulnerability to the speculative execution attack variants"
+	for v in 1 2 3 3a 4; do
 		_info_nol "  * Vulnerable to Variant $v: "
 		if is_cpu_vulnerable $v; then
 			pstatus yellow YES
@@ -2137,7 +2186,10 @@ check_variant2_linux()
 					1)	if [ "$ibrs_fw_enabled" = 1 ]; then pstatus green YES "for kernel space and firmware code"; else pstatus green YES "for kernel space"; fi;;
 					2)	if [ "$ibrs_fw_enabled" = 1 ]; then pstatus green YES "for kernel, user space, and firmware code" ; else pstatus green YES "for both kernel and user space"; fi;;
 					3)	if [ "$ibrs_fw_enabled" = 1 ]; then pstatus green YES "for kernel and firmware code"; else pstatus green YES; fi;;
-					*)	pstatus yellow UNKNOWN;;
+					*)	if [ "$cpuid_ibrs" != 'SPEC_CTRL' ] && [ "$cpuid_ibrs" != 'IBRS_SUPPORT' ] && [ "$cpuid_spec_ctrl" != -1 ]; 
+							then pstatus yellow NO; _debug "ibrs: known cpu not supporting SPEC-CTRL or IBRS"; 
+						else 
+							pstatus yellow UNKNOWN; fi;;
 				esac
 			fi
 		else
@@ -2814,6 +2866,32 @@ check_variant3_bsd()
 	fi
 }
 
+check_variant3a()
+{
+	_info "\033[1;34mCVE-2018-3640 [rogue system register read] aka 'Variant 3a'\033[0m"
+
+	cve='CVE-2018-3640'
+	if ! is_cpu_vulnerable 3a; then
+		# override status & msg in case CPU is not vulnerable after all
+		pvulnstatus $cve OK "your CPU vendor reported your CPU model as not vulnerable"
+	else
+		pvulnstatus $cve UNK "new vulnerability, script will be updated when more technical information is available in the next hours/days"
+	fi
+}
+
+check_variant4()
+{
+	_info "\033[1;34mCVE-2018-3639 [speculative store bypass] aka 'Variant 4'\033[0m"
+
+	cve='CVE-2018-3639'
+	if ! is_cpu_vulnerable 4; then
+		# override status & msg in case CPU is not vulnerable after all
+		pvulnstatus $cve OK "your CPU vendor reported your CPU model as not vulnerable"
+	else
+		pvulnstatus $cve UNK "new vulnerability, script will be updated when more technical information is available in the next hours/days"
+	fi
+}
+
 if [ "$opt_no_hw" = 0 ] && [ -z "$opt_arch_prefix" ]; then
 	check_cpu
 	check_cpu_vulnerabilities
@@ -2833,6 +2911,14 @@ if [ "$opt_variant3" = 1 ] || [ "$opt_allvariants" = 1 ]; then
 	check_variant3
 	_info
 fi
+if [ "$opt_variant3a" = 1 ] || [ "$opt_allvariants" = 1 ]; then
+	check_variant3a
+	_info
+fi
+if [ "$opt_variant4" = 1 ] || [ "$opt_allvariants" = 1 ]; then
+	check_variant4
+	_info
+fi
 
 _vars=$(set | grep -Ev '^[A-Z_[:space:]]' | sort | tr "\n" '|')
 _debug "variables at end of script: $_vars"