Vulnerability in Linux kernel (CVE-2026-89916)
Summary
Vulnerability in Linux kernel (CVE-2026-89916). Successful exploitation can lead to full system takeover.
Original description
The description as published by the source.
In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: Make VNCR invalidation participate in MMU invalidation retry
A VNCR TLB invalidation can occur on one vcpu while another vcpu is
faulting in this same page. Without correctly handling this, we can
end up with the following scenario:
- vcpu A walks the PTs to translate VNCR
- before vcpu A is able to grab the MMU lock to insert the TLB,
vcpu B updates the S1 PTs with an invalid entry, and issues
a TLBI S1E2 for this VA - vcpu A inserts the TLB for something that is now invalid
This isn't a new problem, and we manage S2 by having the MMU notifier
to bump up mmu_invalidate_seq on invalidation so that the fault can be
replayed.
We can perform something similar here, and extend invalidate_vncr_va() to
update the same counter, clearly indicating that the context has
changed under our feet. This is safe as the invalidation always happen
while holding the MMU lock for write, and that we sample the sequence
number before walking S1.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-89916 has been found in Linux kernel.
Successful exploitation can lead to full system takeover. CVSS score: 9.3/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-89916" on the vendor's site.
CVE-2026-89916 (Linux kernel) — CVSS v3 9.3
Attack vector: local / unauthenticated / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (unclassified) exists in Linux kernel.
Check the vendor advisory for the affected versions of Linux kernel.
Severity: Critical (CVSS 9.3/10). Successful exploitation can lead to full system takeover.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Linux kernel を使っているサービスとバージョンを洗い出す。
-
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-89916 linux Fixed in: 7.2.6-1
- Ubuntu UBUNTU-CVE-2026-89916 linux-hwe-edge
References
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web nvd.nist.gov
- web github.com