Summary
ZITADEL: Missing Token Lifecyle Validation (exp and iat) in JWT IdP Provider
A token lifecycle validation vulnerability was discovered in ZITADEL's external JWT Identity Provider (IdP) implementation.
ZITADEL enforces a 1-hour maximum token age freshness window (maxAge) calculated from the token's issue time. However, this safety check is guarded by a presence condition. If an incoming token omits the iat claim, the freshness check is entirely bypassed, allowing arbitrarily old tokens to pass authentication successfully.
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.
Affected Versions
Systems running one of the following versions are affected:
- 4.x:
4.0.0through4.15.1(including RC versions) - 3.x:
3.0.0through3.4.11(including RC versions)
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 your external IdP explicitly includes the iat claim in all signed JWTs.
Publication Note
This advisory covers a subset of the security issues originally published on ZITADEL's registry under this tracking ID. To adhere strictly to CVE formatting standards regarding independently fixable flaws, the original "Token Lifecycle Validation" disclosure has been split into two granular entries. This entry specifically tracks the missing iat claim logic, while a separate companion entry tracks the missing exp claim logic: GHSA-v77h-2w3m-94hx
Questions
If you have any questions or comments about this advisory, please email us at [email protected]
Credits
Thanks to Android-Login-Analysis, Jason Zhou and Pedro Giglioti for reporting this vulnerability.
Impact
An attacker in possession of a stale token lacking an iat claim can reuse it indefinitely without triggering the maximum age freshness invalidation.
CVE-2026-56664 has a CVSS score of 4.2 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.80.0-v2.20.0.20260615122908-fad02c6d9f45); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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The vulnerability has been addressed in the latest releases. ZITADEL now explicitly rejects tokens that lack an iat claim.
Frequently Asked Questions
- What is CVE-2026-56664? CVE-2026-56664 is a medium-severity security vulnerability in github.com/zitadel/zitadel (go), affecting versions < 1.80.0-v2.20.0.20260615122908-fad02c6d9f45. It is fixed in 1.80.0-v2.20.0.20260615122908-fad02c6d9f45.
- How severe is CVE-2026-56664? CVE-2026-56664 has a CVSS score of 4.2 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of github.com/zitadel/zitadel are affected by CVE-2026-56664? github.com/zitadel/zitadel (go) versions < 1.80.0-v2.20.0.20260615122908-fad02c6d9f45 is affected.
- Is there a fix for CVE-2026-56664? Yes. CVE-2026-56664 is fixed in 1.80.0-v2.20.0.20260615122908-fad02c6d9f45. Upgrade to this version or later.
- Is CVE-2026-56664 exploitable, and should I be worried? Whether CVE-2026-56664 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-56664 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-56664? Upgrade
github.com/zitadel/zitadelto 1.80.0-v2.20.0.20260615122908-fad02c6d9f45 or later.