Vulnerability in Linux kernel (CVE-2026-80926)
Summary
Vulnerability in Linux kernel (CVE-2026-80926). 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:
ksmbd: fix use-after-free in oplock break notification
smb2_oplock_break_noti() reads opinfo->conn without any lock and
dereferences it after two allocations which may sleep. When the
durable handle owning the oplock is disconnected, session_fd_check()
clears opinfo->conn and drops its conn reference under ci->m_lock, and
the last ksmbd_conn_put() frees the connection. A break triggered by
another connection that races with the teardown can then resurrect the
freed connection: ksmbd_conn_get() is a plain atomic_inc, and the
queued break work later dereferences the stale conn via
ksmbd_conn_write(), a use-after-free reachable by any authenticated
client holding a durable batch oplock.
Thread the caller's inode into the notification path instead of taking
a new reference on it. Every caller of oplock_break() already holds a
live ksmbd_file (or an explicit ksmbd_inode_lookup_lock() reference,
in the parent lease break paths) on the inode that owns the break
target's oplock list, so ci cannot be freed during the call, and its
lock can be taken without dereferencing opinfo->o_fp, which a
concurrent close may free. Select and pin the connection under
ci->m_lock, the same lock session_fd_check() and
ksmbd_reopen_durable_fd() use to update opinfo->conn, so a concurrent
detach either loses the race to the clear or keeps the connection
alive until the notification work releases it. Transfer the reference
to the…
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-2026-80926 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-2026-80926" on the vendor's site.
CVE-2026-80926 (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-2026-80926 linux Fixed in: 6.12.111-1
- Ubuntu UBUNTU-CVE-2026-80926 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 git.kernel.org
- web github.com