fix(auth): pin JWT validation algorithms to an allowlist#148
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Reject tokens whose header advertises an algorithm outside an asymmetric-only allowlist, preventing RS256->HS256 confusion. Assisted-By: Claude Opus 4.7 <noreply@anthropic.com> Signed-off-by: Sergey Vilgelm <sergey@vilgelm.com>
This was referenced May 25, 2026
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📌 Summary
The JWKS verifier selected the validation algorithm from the token's own header, which lets an attacker choose
alg(RS256 → HS256 algorithm confusion). The verifier now rejects any token whose header advertises an algorithm outside an asymmetric-only allowlist before key lookup.🔍 Related Issues
✨ Changes Made
default_jwks_algorithms()(asymmetric only, noHS*) and re-exportAlgorithm.JsonWebKeySet::verifynow takes an allowed-algorithms slice and rejects disallowedalg.GenericOauthTokenVerifierpasses the default allowlist; unit tests cover HMAC rejection.