Vulnerability in Linux kernel (CVE-2026-90231)
Summary
Vulnerability in Linux kernel (CVE-2026-90231). Confidential information can be exposed externally.
Original description
The description as published by the source.
In the Linux kernel, the following vulnerability has been resolved:
apparmor: fix unconfined user namespace restriction forced stack
If a task is already confined by a stack the unprivileged transition
restriction on unconfined is not correctly, applied. This results in
an escape if two transitions through an unconfined profile can be
executed.
Fix this by pushing the check into the per profile label build. The
check will always be done against unconfined and result in a stack of
just the unconfined component when necessary.
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-2026-90231 has been found in Linux kernel.
Confidential information can be exposed externally. CVSS score: 8.4/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-90231" on the vendor's site.
CVE-2026-90231 (Linux kernel) — CVSS v3 8.4
Attack vector: local / 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: High (CVSS 8.4/10). Confidential information can be exposed externally.
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-2026-90231 linux
- Ubuntu UBUNTU-CVE-2026-90231 linux-hwe-edge
References
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web nvd.nist.gov
- web github.com