Vulnerability in Linux kernel (CVE-2026-64031)
Summary
Vulnerability in Linux kernel (CVE-2026-64031). 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:
erofs: fix managed cache race for unaligned extents
After unaligned compressed extents were introduced, the following race
could occur:
[Thread 1] [Thread 2]
(z_erofs_fill_bio_vec)
...
filemap_add_folio (1)
(z_erofs_bind_cache)
..
..
folio_attach_private (2)
filemap_add_folio (3) again
Since (1) is executed but (2) hasn't been executed yet, it's possible
that another thread finds the same managed folio in z_erofs_bind_cache()
for a different pcluster and calls filemap_add_folio() again since
folio->private is still Z_EROFS_PREALLOCATED_FOLIO.
Fix this by explicitly clearing folio->private before making the folio
visible in the managed cache so that another pcluster can simply wait
on the locked managed folio as what we did for other shared cases [1].
This only impacts unaligned data compression (-E48bit with zstd,
for example).
[1] Commit 9e2f9d34dd12 ("erofs: handle overlapped pclusters out of
crafted images properly") was originally introduced to handle crafted
overlapped extents, but it addresses unaligned extents as well.
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-2026-64031 has been found in Linux kernel.
Successful exploitation can lead to full system takeover. CVSS score: 7.8/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-64031" on the vendor's site.
CVE-2026-64031 (Linux kernel) — CWE-362 / CVSS v3 7.8
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 (CWE-362) exists in Linux kernel.
Check the vendor advisory for the affected versions of Linux kernel.
Severity: High (CVSS 7.8/10). 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。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- BellSoft Alpaquita BELL-CVE-2026-64031 linux-lts Fixed in: 6.18.35-r1
- Debian DEBIAN-CVE-2026-64031 linux Fixed in: 7.0.12-1
- Ubuntu UBUNTU-CVE-2026-64031 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 github.com
- web git.kernel.org