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CVE-2026-59877
medium
CVSS 5.3
Vulnerability in protobufjs (CVE-2026-59877)
Summary
vulnerability in protobufjs (CVE-2026-59877). Risk of unauthorized operations or information disclosure. Exploitable via ``parse``. Mitigation: upgrade to `8.6.6` or later.
AI summary snake-internal / snake-material-v2
A vulnerability tracked as **CVE-2026-59877** has been found in protobufjs.
Attackers can target a specific entry point like ``parse`` over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 5.3/10.
What to do: upgrade protobufjs to **8.6.6** or later.
If unsure, ask your IT team or search "protobufjs CVE-2026-59877" on the vendor's site.
CVE-2026-59877 (protobufjs) — CWE-835 / CVSS v3 5.3
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: `parse` / `Root.load` / `Root.loadSync`
Patched: `8.6.6` — apply immediately
Workaround: Do not parse `.proto` schemas from untrusted sources with affected versions.
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-835) exists in protobufjs. Attackers reach the vulnerable code path via ``parse`` without authentication.
📍 Affected scope
protobufjs — . Attack surface: `parse` / `Root.load` / `Root.loadSync`.
🔥 Severity
Severity: Medium (CVSS 5.3/10). Risk of unauthorized operations or information disclosure
🔧 How to fix
Update to **8.6.6**.
🛡️ Workaround
Workaround: Do not parse `.proto` schemas from untrusted sources with affected versions.
🔍 Detection
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run `grep -r 'protobufjs' .` 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
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1Identify exposure identify
grep -r 'protobufjs' . | 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 `protobufjs` を grep し、稼働しているサービス・バージョンを把握する。
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5Apply temporary workaround mitigate
Do not parse `.proto` schemas from untrusted sources with affected versions.パッチが適用されるまでの応急処置として、Do not parse `.proto` schemas from untrusted sources with affected versions. を実施。回避策の副作用 (機能低下) を確認した上で。
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6Apply patch patch
Upgrade protobufjs to 8.6.6ステージング環境で 8.6.6 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。
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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
protobufjs
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"8.6.6"}]}]
References
- web https://github.com/protobufjs/protobuf.js/commit/10fba6d54815ceecca8a06b9a6db490c8f5d2217
- web https://github.com/protobufjs/protobuf.js/commit/fa5c73add738ceb471e74da8cc2f3727c3d0a69f
- web https://github.com/protobufjs/protobuf.js/pull/2352
- web https://github.com/protobufjs/protobuf.js/releases/tag/protobufjs-v7.6.5
- web https://github.com/protobufjs/protobuf.js/releases/tag/protobufjs-v8.6.6
- web https://github.com/protobufjs/protobuf.js/security/advisories/GHSA-j3f2-48v5-ccww
- web https://nvd.nist.gov/vuln/detail/CVE-2026-59877
- web https://github.com/advisories/GHSA-j3f2-48v5-ccww