Vulnerability in Linux kernel (CVE-2026-43090)
Summary
Vulnerability in Linux kernel (CVE-2026-43090). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
In the Linux kernel, the following vulnerability has been resolved:
xfrm: fix refcount leak in xfrm_migrate_policy_find
syzkaller reported a memory leak in xfrm_policy_alloc:
BUG: memory leak
unreferenced object 0xffff888114d79000 (size 1024):
comm "syz.1.17", pid 931
...
xfrm_policy_alloc+0xb3/0x4b0 net/xfrm/xfrm_policy.c:432
The root cause is a double call to xfrm_pol_hold_rcu() in
xfrm_migrate_policy_find(). The lookup function already returns
a policy with held reference, making the second call redundant.
Remove the redundant xfrm_pol_hold_rcu() call to fix the refcount
imbalance and prevent the memory leak.
Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
Source: GitHub Security Advisories (Global) 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-2026-43090 has been found in Linux kernel.
Risk of unauthorized operations or information disclosure. CVSS score: 5.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-43090" on the vendor's site.
CVE-2026-43090 (Linux kernel) — CVSS v3 5.5
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: Medium (CVSS 5.5/10). Risk of unauthorized operations or information disclosure.
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。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- BellSoft Alpaquita BELL-CVE-2026-43090 linux-lts Fixed in: 6.12.85-r0
- Debian DEBIAN-CVE-2026-43090 linux Fixed in: 6.12.85-1
- Ubuntu UBUNTU-CVE-2026-43090 linux-hwe-edge
References
- advisory nvd.nist.gov
- advisory github.com
- package git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web github.com