CVE-2026-13089 Auth bypass in OIDC::Lite
Attackers can bypass ID Token signature verification in OIDC::Lite by manipulating the algorithm header, allowing authentication as any user.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-13089?
CVE-2026-13089 is a high-severity authentication bypass vulnerability in RITOU OIDC::Lite, published on 22 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
OIDC::Lite versions through 0.12.1 for Perl allow ID Token signature verification bypass via a token-controlled algorithm allowlist in verify.
When the caller does not pin an algorithm, OIDC::Lite::Model::IDToken::verify sets $self->alg($self->header->{alg}) from the token's own header and then calls decode_jwt(token, key, 1, [$self->alg]), handing JSON::WebToken an accepted-algorithm allowlist taken from the untrusted token. A token with alg=none yields ['none'], so decode_jwt returns the claims with no signature check, and a token with alg=HS256 is verified with the RP's RSA public key as the HMAC secret (RS to HS confusion).
The ID Token is the OpenID Connect authentication assertion delivered to the Relying Party. Any caller that verifies an ID Token through the unpinned load(token)->verify path, or load(token, key) with only the key pinned, accepts a forged token carrying attacker-chosen claims such as sub and is authenticated as any user. Passing an explicit algorithm so $self->alg is already set bypasses the header-derived allowlist and is not affected.
Note that the latest version uploaded to CPAN is 0.10. Later versions are available in the git repository.
Weakness: CWE-347
Which versions are affected by CVE-2026-13089?
How do I fix CVE-2026-13089?
No fix has been published for CVE-2026-13089 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-13089 being exploited?
There is no known exploitation of CVE-2026-13089 in the wild and no public exploit code.
Sources
Also known as GHSA-fr32-wcm4-p6hf.