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CVE-2026-43966
Vulnerability in cowlib (CVE-2026-43966)
Summary
vulnerability in cowlib (CVE-2026-43966). Risk of unauthorized operations or information disclosure.
AI summary snake-internal / snake-material-v2
A vulnerability tracked as **CVE-2026-43966** has been found in cowlib.
Risk of unauthorized operations or information disclosure. CVSS score: ?/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "cowlib CVE-2026-43966" on the vendor's site.
CVE-2026-43966 (cowlib) — CWE-113 /
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
**A vulnerability** (CWE-113) exists in cowlib.
📍 Affected scope
cowlib — .
🔥 Severity
Severity: ?. Risk of unauthorized operations or information disclosure
🔧 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 'cowlib' .` 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 'cowlib' . | 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 `cowlib` 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。
Affected packages
Hex
cowlib
[{"type":"SEMVER","events":[{"introduced":"2.9.0"}]}]
References
- package https://hex.pm/packages/cowlib
- web https://cna.erlef.org/cves/CVE-2026-43966.html
- web https://github.com/ninenines/cowboy/commit/f77cb9b5e730e300fffb551db1ba5d1c4ed878ef
- web https://github.com/ninenines/gun/commit/4f35609eb37109b106a863fc9ba83d7ee64e3e42
- web 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
- web https://nvd.nist.gov/vuln/detail/CVE-2026-43966
- web https://github.com/advisories/GHSA-w4f7-4cxr-rv3c