Vulnerability in Linux kernel (CVE-2026-64264)
Summary
Vulnerability in Linux kernel (CVE-2026-64264). 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:
fuse-uring: fix EFAULT clobber in fuse_uring_commit
copy_from_user() returns the number of bytes not copied as an unsigned
residual on failure (1..sizeof(struct fuse_out_header)). fuse_uring_commit
stores that residual in ssize_t err, sets req->out.h.error to -EFAULT,
then jumps to out: with err still holding the positive residual.
err = copy_from_user(&req->out.h, &ent->headers->in_out,
sizeof(req->out.h));
if (err) {
req->out.h.error = -EFAULT;
goto out; /* err is the positive residual */
}
...
out:
fuse_uring_req_end(ent, req, err);
fuse_uring_req_end() then runs
if (error)
req->out.h.error = error;
which overwrites the just-assigned -EFAULT with the positive residual.
FUSE callers such as fuse_simple_request() test err < 0 to detect
failure, so the positive value is interpreted as success and the
caller proceeds with an uninitialised or partial req->out.args.
Fix by assigning err = -EFAULT in the failure branch before jumping
to out, so fuse_uring_req_end() receives a negative errno and sets
req->out.h.error to -EFAULT.
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-2026-64264 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-2026-64264" on the vendor's site.
CVE-2026-64264 (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-2026-64264 linux-lts Fixed in: 6.18.43-r0
- Debian DEBIAN-CVE-2026-64264 linux Fixed in: 7.1.4-1
- Ubuntu UBUNTU-CVE-2026-64264 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