← Back
CVE-2026-59869
high
CVSS 7.5
Vulnerability in js-yaml (CVE-2026-59869)
Summary
vulnerability in js-yaml (CVE-2026-59869). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to `4.3.0` or later.
AI summary snake-internal / snake-material-v2
A vulnerability tracked as **CVE-2026-59869** has been found in js-yaml.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: upgrade js-yaml to **4.3.0** or later.
If unsure, ask your IT team or search "js-yaml CVE-2026-59869" on the vendor's site.
CVE-2026-59869 (js-yaml) — CWE-400 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: `4.3.0` — apply immediately
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-400) exists in js-yaml.
📍 Affected scope
js-yaml — .
🔥 Severity
Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure
🔧 How to fix
Update to **4.3.0**.
🛡️ 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 'js-yaml' .` 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 'js-yaml' . | 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 `js-yaml` を grep し、稼働しているサービス・バージョンを把握する。
-
6Apply patch patch
Upgrade js-yaml to 4.3.0ステージング環境で 4.3.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスと、Step 3 で見つけた異常検知の続報チェックを含めること。
-
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
npm
js-yaml
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.3.0"}]}]
References
- web https://github.com/nodeca/js-yaml/commit/24f13e79ee1343a7e30bd6f6c9d9cdbf0ac9b2b7
- web https://github.com/nodeca/js-yaml/commit/59423c6f8cdc78742ac00e25a4dd39ef16b702e4
- web https://github.com/nodeca/js-yaml/releases/tag/3.15.0
- web https://github.com/nodeca/js-yaml/releases/tag/4.3.0
- web https://github.com/nodeca/js-yaml/security/advisories/GHSA-52cp-r559-cp3m
- web https://nvd.nist.gov/vuln/detail/CVE-2026-59869
- web https://github.com/advisories/GHSA-52cp-r559-cp3m