Vulnerability in Linux kernel (CVE-2026-43266)
Summary
Vulnerability in Linux kernel (CVE-2026-43266). 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:
EFI/CPER: don't go past the ARM processor CPER record buffer
There's a logic inside GHES/CPER to detect if the section_length
is too small, but it doesn't detect if it is too big.
Currently, if the firmware receives an ARM processor CPER record
stating that a section length is big, kernel will blindly trust
section_length, producing a very long dump. For instance, a 67
bytes record with ERR_INFO_NUM set 46198 and section length
set to 854918320 would dump a lot of data going a way past the
firmware memory-mapped area.
Fix it by adding a logic to prevent it to go past the buffer
if ERR_INFO_NUM is too big, making it report instead:
[Hardware Error]: Hardware error from APEI Generic Hardware Error Source: 1
[Hardware Error]: event severity: recoverable
[Hardware Error]: Error 0, type: recoverable
[Hardware Error]: section_type: ARM processor error
[Hardware Error]: MIDR: 0xff304b2f8476870a
[Hardware Error]: section length: 854918320, CPER size: 67
[Hardware Error]: section length is too big
[Hardware Error]: firmware-generated error record is incorrect
[Hardware Error]: ERR_INFO_NUM is 46198
[ rjw: Subject and changelog tweaks ]
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-2026-43266 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-2026-43266" on the vendor's site.
CVE-2026-43266 (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-2026-43266 linux-lts Fixed in: 6.1.167-r0
- Debian DEBIAN-CVE-2026-43266 linux Fixed in: 5.10.257-1
- Ubuntu UBUNTU-CVE-2026-43266 linux
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 git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web github.com