KVM: arm64: Remove VM-wide VNCR mapping counter
In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: Remove VM-wide VNCR mapping counter The global VNCR mapping counter is used to decide whether an L1 provided VNCR page is mapped in L0 on any CPU at the point of dealing with a TLB invalidation. It is incremented when a mapping is made in the fixmap, and decremented when unmapped. As it turns out, this tracking has several flaws: - we are trying to invalidate TLBs, and the mapping is only an opportunistic consequence of the TLB. Checking this counter to decide whether a TLB needs to be invalidated may result in missed invalidations. - an L1 vcpu invalidating its own TLB (a very likely case) will not succeed in invalidating the VNCR pseudo TLB because that page is not mapped in L0 at this stage. Given that this tracking fails at delivering the minimum guarantees that are required and is only a performance optimisation, remove it completely.
CVE-2026-89915
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-2026-89915
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": "4ffa72ad8f37e73bbb6c0baa88557bcb4fd39929",
"lessThan": "5453b85c7ebb605febac3df42021f9471663f051",
"versionType": "git"
},
{
"status": "affected",
"version": "4ffa72ad8f37e73bbb6c0baa88557bcb4fd39929",
"lessThan": "87c2bbf189829dce4aaada8f82e3d54ccc037976",
"versionType": "git"
},
{
"status": "affected",
"version": "4ffa72ad8f37e73bbb6c0baa88557bcb4fd39929",
"lessThan": "c55bc773b6e814406658fae7dc5c15f639ed816e",
"versionType": "git"
}
],
"programFiles": [
"arch/arm64/include/asm/kvm_host.h",
"arch/arm64/kvm/hyp/vhe/switch.c",
"arch/arm64/kvm/nested.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.16"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.16",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.18.52",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"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/kvm_host.h",
"arch/arm64/kvm/hyp/vhe/switch.c",
"arch/arm64/kvm/nested.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-89915
Source reference:
/cveMetadata/cveId
Publisher severity
critical
Source reference: /containers/cna/metrics
- Event
- #36360 · Revision 1
- Added to Heist Feed
- Publisher date