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CVE-2025-21999
high
CVSS 7.8
Use-After-Free in linux (CVE-2025-21999)
Summary
vulnerability in linux (CVE-2025-21999). Successful exploitation can lead to full system takeover.
AI summary snake-internal / snake-material-v2
A vulnerability tracked as **CVE-2025-21999** has been found in linux.
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 CVE-2025-21999" on the vendor's site.
CVE-2025-21999 (linux) — CWE-416 / 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.
❓ What is the problem
**use-after-free** (CWE-416) exists in linux.
📍 Affected scope
linux — .
🔥 Severity
Severity: High (CVSS 7.8/10). Successful exploitation can lead to full system takeover
🔧 How to fix
Update to the patched release per vendor advisory.
🛡️ Workaround
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
🔍 Detection
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run `grep -r 'linux' .` against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response Actions (7 steps)
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'linux' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で `linux` を grep し、稼働しているサービス・バージョンを把握する。
-
7Post-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 Step 3 と同じログクエリでアラート再発が無いか継続監視。
References
- web https://git.kernel.org/stable/c/4b0b8445b6fd41e6f62ac90547a0ea9d348de3fa
- web https://git.kernel.org/stable/c/63b53198aff2e4e6c5866a4ff73c7891f958ffa4
- web https://git.kernel.org/stable/c/64dc7c68e040251d9ec6e989acb69f8f6ae4a10b
- web https://git.kernel.org/stable/c/654b33ada4ab5e926cd9c570196fefa7bec7c1df
- web https://git.kernel.org/stable/c/966f331403dc3ed04ff64eaf3930cf1267965e53
- web https://git.kernel.org/stable/c/eda279586e571b05dff44d48e05f8977ad05855d
- web https://git.kernel.org/stable/c/ede3e8ac90ae106f0b29cd759aadebc1568f1308
- web https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html
- web https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html
- web https://cert-portal.siemens.com/productcert/html/ssa-019113.html
- web https://nvd.nist.gov/vuln/detail/CVE-2025-21999
- web https://github.com/advisories/GHSA-vmv5-h8c6-426p