RITOU OIDC::Lite up to 0.12.1 ID Token Verification verify alg signature verification

Summaryinfo

A vulnerability was found in RITOU OIDC::Lite up to 0.12.1. It has been declared as critical. This issue affects the function OIDC::Lite::Model::IDToken::verify of the component ID Token Verification. Such manipulation of the argument alg leads to signature verification. This vulnerability is referenced as CVE-2026-13089. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability, which was classified as critical, has been found in RITOU OIDC::Lite up to 0.12.1. Affected by this issue is the function OIDC::Lite::Model::IDToken::verify of the component ID Token Verification. The manipulation of the argument alg with an unknown input leads to a signature verification vulnerability. Using CWE to declare the problem leads to CWE-347. The product does not verify, or incorrectly verifies, the cryptographic signature for data. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is available at datatracker.ietf.org. This vulnerability is handled as CVE-2026-13089 since 06/23/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 07/22/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

• RITOU

Name

• OIDC::Lite

Version

• 0.12.0
• 0.12.1

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