AIKIDO-2026-530808
guardian is vulnerable to Improper Verification of Cryptographic Signature
82
CVE Score
High
Improper Verification of Cryptographic Signature
TL;DR
Guardian.revoke/3 in lib/guardian.ex acts on JWT claims obtained through peek, which performs no signature verification. A caller-supplied token is decoded without checking its signature, so forged claim values reach the token module's revoke and on_revoke callbacks. Before the fix, someone who knows a target's jti and sub claim values can forge a token and force revocation of that session without possessing the signing secret. The fix decodes and verifies the token signature before invoking the revoke callbacks while still allowing already-expired tokens to be revoked.
How do I fix this?
Upgrade the guardian library to the patch version.
Who does this affect?
You are affected if you are using a version that falls within the vulnerable range and your application routes a caller-supplied token into Guardian.revoke/3 with a token module that mutates session state keyed by token claims.
Package
Versions
1.0.0 - 2.4.0
Fixed in 2.4.1Background info
guardian is vulnerable to Improper Verification of Cryptographic Signature in versions 1.0.0 - 2.4.0.
Links
GitHub Release
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