Vulnerability in Linux kernel (CVE-2025-21661)
Summary
Vulnerability in Linux kernel (CVE-2025-21661). 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:
gpio: virtuser: fix missing lookup table cleanups
When a virtuser device is created via configfs and the probe fails due
to an incorrect lookup table, the table is not removed. This prevents
subsequent probe attempts from succeeding, even if the issue is
corrected, unless the device is released. Additionally, cleanup is also
needed in the less likely case of platform_device_register_full()
failure.
Besides, a consistent memory leak in lookup_table->dev_id was spotted
using kmemleak by toggling the live state between 0 and 1 with a correct
lookup table.
Introduce gpio_virtuser_remove_lookup_table() as the counterpart to the
existing gpio_virtuser_make_lookup_table() and call it from all
necessary points to ensure proper cleanup.
Source: NIST National Vulnerability Database NVD
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-2025-21661 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-2025-21661" on the vendor's site.
CVE-2025-21661 (Linux kernel) — CWE-401 / 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-401) 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-2025-21661 linux-lts Fixed in: 6.12.41-r0
- Debian DEBIAN-CVE-2025-21661 linux Fixed in: 6.12.10-1
- Ubuntu UBUNTU-CVE-2025-21661 linux-hwe-edge
References
- advisory github.com
- advisory nvd.nist.gov
- package git.kernel.org
- web git.kernel.org
- web git.kernel.org