Summary
OpenFGA: OIDC audience validation skipped when --authn-oidc-audience is unset
Full technical description
Description
OpenFGA's OIDC authenticator skipped JWT audience (aud) validation when no audience was configured.
In deployments where one identity provider issues tokens for multiple services,
a token minted for an unrelated service could authenticate to OpenFGA.
Preconditions
This applies if the following preconditions are met:
- You run OpenFGA with
authn.methodset tooidc. - You configured
authn.oidc.issuerbut did not setauthn.oidc.audience(--authn-oidc-audience/OPENFGA_AUTHN_OIDC_AUDIENCE).
Acknowledgements
OpenFGA would like to thank https://github.com/0xVijay for the report.
Impact
The application does not adequately verify the identity of a user, device, or process before granting access. Typical impact: unauthorized access to functions or data reserved for authenticated parties.
CVE-2026-55689 has a CVSS score of 6.8 (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 (1.18.0); 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.
Already deployed Kodem?
See it in your environmentNew to Kodem? Get a demo →Remediation advice
Upgrade to OpenFGA 1.18.0 or greater. OpenFGA now refuses to start in oidc
mode unless both authn.oidc.issuer and authn.oidc.audience are set, and theaud claim is always validated.
Frequently Asked Questions
- What is CVE-2026-55689? CVE-2026-55689 is a medium-severity improper authentication vulnerability in github.com/openfga/openfga (go), affecting versions <= 1.17.1. It is fixed in 1.18.0. The application does not adequately verify the identity of a user, device, or process before granting access.
- How severe is CVE-2026-55689? CVE-2026-55689 has a CVSS score of 6.8 (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/openfga/openfga are affected by CVE-2026-55689? github.com/openfga/openfga (go) versions <= 1.17.1 is affected.
- Is there a fix for CVE-2026-55689? Yes. CVE-2026-55689 is fixed in 1.18.0. Upgrade to this version or later.
- Is CVE-2026-55689 exploitable, and should I be worried? Whether CVE-2026-55689 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-2026-55689 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-2026-55689? Upgrade
github.com/openfga/openfgato 1.18.0 or later.