Vulnerability in Linux kernel (CVE-2026-80561)
Summary
Vulnerability in Linux kernel (CVE-2026-80561). 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:
libceph: fix multiple unsafe decodes in decode_locker()
decode_locker() in cls_lock_client.c contains three unsafe decode
operations that allow a malicious or compromised OSD to trigger
slab-out-of-bounds reads:
-
ceph_decode_copy() at the locker_id_t name field has no preceding
bounds check. With p == end after ceph_start_decoding() accepts
struct_len=0, this reads sizeof(ceph_entity_name) = 9 bytes past
the validated buffer boundary. -
*p += sizeof(struct ceph_timespec) after the locker_info_t header
is an unchecked pointer advance. A malicious OSD can position p
past end, causing all subsequent _safe checks to pass against a
bogus boundary. -
len = ceph_decode_32(p) has no preceding bounds check, and the
immediately following *p += len is uncapped. A malicious OSD can
send len=0xffffffff, advancing p gigabytes past end and escaping
the decode window entirely.
Fix all three by replacing bare operations with their safe variants:
ceph_decode_copy -> ceph_decode_copy_safe
*p += sizeof(...) -> ceph_decode_skip_n
ceph_decode_32(p) -> ceph_decode_32_safe
*p += len -> ceph_decode_skip_n
A new label is added to return -EINVAL on any bounds violation.
-EINVAL is appropriate here: the data received from the OSD
is structurally malformed, which is an invalid argument to the decode
contract regardless of whether the caller or the wire is at fault.
Attacker mode…
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-2026-80561 has been found in Linux kernel.
Successful exploitation can lead to full system takeover. CVSS score: 9.8/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-80561" on the vendor's site.
CVE-2026-80561 (Linux kernel) — CVSS v3 9.8
Attack vector: remote (network-reachable) / unauthenticated / 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: Critical (CVSS 9.8/10). 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
- Debian DEBIAN-CVE-2026-80561 linux Fixed in: 6.1.187-1
- Ubuntu UBUNTU-CVE-2026-80561 linux-azure
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