Vulnerability in lcobucci/jwt (CVE-2021-41106)
Summary
Vulnerability in lcobucci/jwt (CVE-2021-41106). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 4.1.5 or later.
Original description
The description as published by the source.
Impact
Users of HMAC-based algorithms (HS256, HS384, and HS512) combined with Lcobucci\JWT\Signer\Key\LocalFileReference as key are having their tokens issued/validated using the file path as hashing key - instead of the contents.
The HMAC hashing functions take any string as input and, since users can issue and validate tokens, people are lead to believe that everything works properly.
Patches
All versions have been patched to always load the file contents, deprecated the Lcobucci\JWT\Signer\Key\LocalFileReference, and suggest Lcobucci\JWT\Signer\Key\InMemory as the alternative.
Workarounds
Use Lcobucci\JWT\Signer\Key\InMemory instead of Lcobucci\JWT\Signer\Key\LocalFileReference to create the instances of your keys:
-use Lcobucci\JWT\Signer\Key\LocalFileReference;
+use Lcobucci\JWT\Signer\Key\InMemory;
-$key = LocalFileReference::file(__DIR__ . '/public-key.pem');
+$key = InMemory::file(__DIR__ . '/public-key.pem');
Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV
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-2021-41106 has been found in lcobucci/jwt.
Risk of unauthorized operations or information disclosure.
What to do: upgrade lcobucci/jwt to 4.1.5 or later.
If unsure, ask your IT team or search "lcobucci/jwt CVE-2021-41106" on the vendor's site.
CVE-2021-41106 (lcobucci/jwt) — CWE-345
Attack vector: local / no user interaction
Patched: 4.1.5 — 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.
A vulnerability (CWE-345) exists in lcobucci/jwt.
Check the vendor advisory for the affected versions of lcobucci/jwt.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 4.1.5.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'lcobucci/jwt' . 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 'lcobucci/jwt' . | 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
lcobucci/jwtを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade lcobucci/jwt to 4.1.5ステージング環境で 4.1.5 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。
-
3Post-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 nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com
- web github.com