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CVE-2025-21858
high
CVSS 7.8
Use-After-Free in c (CVE-2025-21858)
Summary
vulnerability in c (CVE-2025-21858). Successful exploitation can lead to full system takeover.
AI summary snake-internal / snake-material-v2
A vulnerability tracked as **CVE-2025-21858** has been found in c.
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 "c CVE-2025-21858" on the vendor's site.
CVE-2025-21858 (c) — 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 c.
📍 Affected scope
c — .
🔥 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 'c' .` 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 'c' . | 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 `c` 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/3ce92ca990cfac88a87c61df3cc0b5880e688ecf
- web https://git.kernel.org/stable/c/5a0538ac6826807d6919f6aecbb8996c2865af2c
- web https://git.kernel.org/stable/c/788dbca056a8783ec063da3c9d49a3a71c76c283
- web https://git.kernel.org/stable/c/904e746b2e7fa952ab8801b303ce826a63153d78
- web https://git.kernel.org/stable/c/9593172d93b9f91c362baec4643003dc29802929
- web https://git.kernel.org/stable/c/d5e86e27de0936f3cb0a299ce519d993e9cf3886
- web https://git.kernel.org/stable/c/da9b0ae47f084014b1e4b3f31f70a0defd047ff3
- web https://git.kernel.org/stable/c/f74f6560146714241c6e167b03165ee77a86e316
- 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-265688.html
- web https://nvd.nist.gov/vuln/detail/CVE-2025-21858
- web https://github.com/advisories/GHSA-r9xq-fh23-wm6f