### Summary A token lifecycle validation vulnerability was discovered in ZITADEL's external JWT Identity Provider (IdP) implementation Specifically, within the validation pipeline, if an incoming JWT omits the `exp` claim entirely, the expiration block is silently skipped rather than rejected. The token is treated as valid forever. Per the OIDC Core 1.0 specification, identity token validation pipelines must strictly handle and enforce session expiration. ZITADEL's silent acceptance of tokens missing these temporal constraints compromises session integrity. ### Impact An attacker in possession of a token lacking an `exp` claim holds a permanent credential with no automatic expiration or revocation window. ### Affected Versions Systems running one of the following versions are affected: * **4.x**: `4.0.0` through `4.15.1` (including RC versions) * **3.x**: `3.0.0` through `3.4.11` (including RC versions) ### Patches The vulnerability has been addressed in the latest releases. ZITADEL now explicitly rejects tokens that lack an `exp` claim. * **4.x**: Upgrade to $\ge$ [4.15.2](https://github.com/zitadel/zitadel/releases/tag/v4.15.2) * **3.x**: Upgrade to $\ge$ [3.4.12](https://github.com/zitadel/zitadel/releases/tag/v3.4.12) ### Workarounds The recommended solution is to update ZITADEL to a patched version. If an immediate upgrade is not feasible, ensure at the upstream Identity Provider level that an external IdP explicitly includes the `exp` claim in all signed JWTs. ### Publication Note This issue was originally disclosed as part of a unified security bulletin published under [GHSA-wxg7-w2v3-w38g](https://github.com/zitadel/zitadel/security/advisories/GHSA-wxg7-w2v3-w38g). To satisfy CVE Numbering Authority regulations regarding independently fixable logic flaws, the missing token expiration validation (`exp`) has been moved into this separate tracking entry so a distinct CVE ID can be correctly mapped to it. ### Questions If there are any questions or comments about this advisory, send an email to [[email protected]](mailto:[email protected]) ### Credits ZITADEL thanks [Android-Login-Analysis](https://github.com/Android-Login-Analysis), Jason Zhou and [Pedro Giglioti](https://github.com/Punisher100) for reporting this vulnerability.