The vulnerability allows a malicious actor to exploit the OAuth flow used by sigstore‑python because the "state" value sent in the authentication request is not verified against the value returned by the identity provider. This omission can enable a CSRF attack that forces a user to authenticate and sign data without their consent, potentially generating signatures that are trusted by downstream systems.

Linux Foundation’s sigstore‑python library, any installation of versions earlier than 4.2.0 used for generating or verifying Sigstore signatures. The patch was released in version 4.2.0 and removes the state‑verification flaw.

The EPSS score is below 1 % and the vulnerability is not listed in CISA’s KEV catalog, suggesting a low probability of exploitation in the wild. However, the attack vector is a classic CSRF scenario, making it trivial to construct if the application exposes the login flow to a web context. Given the potential for forged signatures, the risk to integrity and trust is significant even with a low exploitation likelihood.