Use-After-Free in Linux kernel (CVE-2025-39826)
Summary
Vulnerability in Linux kernel (CVE-2025-39826). 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:
net: rose: convert 'use' field to refcount_t
The 'use' field in struct rose_neigh is used as a reference counter but
lacks atomicity. This can lead to race conditions where a rose_neigh
structure is freed while still being referenced by other code paths.
For example, when rose_neigh->use becomes zero during an ioctl operation
via rose_rt_ioctl(), the structure may be removed while its timer is
still active, potentially causing use-after-free issues.
This patch changes the type of 'use' from unsigned short to refcount_t and
updates all code paths to use rose_neigh_hold() and rose_neigh_put() which
operate reference counts atomically.
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-2025-39826 has been found in Linux kernel.
Successful exploitation can lead to full system takeover. CVSS score: 8.8/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2025-39826" on the vendor's site.
CVE-2025-39826 (Linux kernel) — CWE-416 / CVSS v3 8.8
Attack vector: adjacent-network / 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.
Use-after-free (CWE-416) exists in Linux kernel.
Check the vendor advisory for the affected versions of Linux kernel.
Severity: High (CVSS 8.8/10). 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-2025-39826 linux-lts Fixed in: 6.1.151-r0
- Debian DEBIAN-CVE-2025-39826 linux
- Ubuntu UBUNTU-CVE-2025-39826 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 lists.debian.org
- web cert-portal.siemens.com
- web github.com
- web cert-portal.siemens.com
- web cert-portal.siemens.com