arm64: Don't read GMID_EL1 when MTE is disabled
In the Linux kernel, the following vulnerability has been resolved: arm64: Don't read GMID_EL1 when MTE is disabled __cpuinfo_store_cpu() gates the GMID_EL1 read on the raw ID_AA64PFR1_EL1, so it reads the register even when the kernel has disabled MTE (CONFIG_ARM64_MTE=n or arm64.nomte). KVM sets HCR_EL2.TID5 in that case, and pKVM injects an UNDEF the host cannot handle: Internal error: Oops - Undefined instruction: 0000000002000000 [#1] SMP pc : __cpuinfo_store_cpu+0xf4/0x264 Kernel panic - not syncing: Attempted to kill the idle task! Only pKVM reaches it, and only after a CPU is offlined and brought back online: its CPU_ON relay sets the host HCR before the CPU enters EL1, while plain nVHE sets it at CPUHP_AP_KVM_ONLINE. Gate the read on the CPU's own ID_AA64PFR1_EL1 with the command-line override applied, and on CONFIG_ARM64_MTE, which no register reflects. The boot CPU stores its registers before init_cpu_features() strips an unsafe override, so clamp against the hardware value here too.
CVE-2026-89981
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-89981
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "f35abcbb8a084db4c24b66ccc8db0405c08e2f61",
"lessThan": "d2d22ff377cd43f2e9660426ff22e3cd4c534637",
"versionType": "git"
},
{
"status": "affected",
"version": "f35abcbb8a084db4c24b66ccc8db0405c08e2f61",
"lessThan": "5445d64199626974269fcdf347769ad44b0bb53b",
"versionType": "git"
}
],
"programFiles": [
"arch/arm64/include/asm/cpu.h",
"arch/arm64/include/asm/cpufeature.h",
"arch/arm64/kernel/cpufeature.c",
"arch/arm64/kernel/cpuinfo.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "7.0"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "7.0",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "7.2.5",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"arch/arm64/include/asm/cpu.h",
"arch/arm64/include/asm/cpufeature.h",
"arch/arm64/kernel/cpufeature.c",
"arch/arm64/kernel/cpuinfo.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-89981
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #36418 · Revision 1
- Added to Heist Feed
- Publisher date