Vulnerability in protobufjs (CVE-2026-44291)
Summary
Vulnerability in protobufjs (CVE-2026-44291). Successful exploitation can lead to full system takeover. Exploitable via Object.prototype. Mitigation: upgrade to 8.0.2 or later.
Original description
The description as published by the source.
protobufjs compiles protobuf definitions into JavaScript (JS) functions. Prior to 7.5.6 and 8.0.2, protobufjs used plain objects with inherited prototypes for internal type lookup tables used by generated encode and decode functions. If Object.prototype had already been polluted, those lookup tables could resolve attacker-controlled inherited properties as valid protobuf type information. This could cause attacker-controlled strings to be emitted into generated JavaScript code. This vulnerability is fixed in 7.5.6 and 8.0.2.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-44291 has been found in protobufjs.
Attackers can target a specific entry point like Object.prototype over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: 8.1/10.
What to do: upgrade protobufjs to 8.0.2 or later.
If unsure, ask your IT team or search "protobufjs CVE-2026-44291" on the vendor's site.
CVE-2026-44291 (protobufjs) — CWE-1321 / CVSS v3 8.1
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: Object.prototype
Patched: 8.0.2 — apply immediately
Workaround: Avoid running affected versions in applications where attacker-controlled input can pollute Object.prototype.
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.
A vulnerability (CWE-1321) exists in protobufjs. Attackers reach the vulnerable code path via Object.prototype without authentication.
Check the vendor advisory for the affected versions of protobufjs. Attack surface: Object.prototype.
Severity: High (CVSS 8.1/10). Successful exploitation can lead to full system takeover.
Update to 8.0.2.
Workaround: Avoid running affected versions in applications where attacker-controlled input can pollute Object.prototype.
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
Concrete steps and command examples for SOC/SRE teams to execute in order
-
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。 -
2Apply temporary workaround mitigate
Avoid running affected versions in applications where attacker-controlled input can pollute `Object.prototype`.パッチが適用されるまでの応急処置として、Avoid running affected versions in applications where attacker-controlled input can pollute
Object.prototype. を実施。回避策の副作用 (機能低下) を確認した上で。 -
3Apply patch patch
Upgrade protobufjs to 8.0.2ステージング環境で 8.0.2 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を含めること。
-
4Post-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。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com
- package github.com
- web github.com
- web github.com
- web github.com