CVE-2026-55689: OpenFGA OIDC Audience Validation Skipped When Vulnerability

MODERATE
Advisory Identifier: GHSA-hcxc-wf8j-23hv
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CVSS 6.8
CWE-287
Published
Advisory Summary

CVE-2026-55689 is a MODERATE (CVSS 6.8) oidc audience validation skipped when vulnerability (CWE-287: Improper Authentication) affecting OpenFGA libraries in the Go ecosystem. The issue involves oidc audience validation skipped when --authn-oidc-audience is unset. Remediation is available by upgrading affected packages to version 1.18.0.

CVE-2026-55689 at a Glance

CVE Identifier CVE-2026-55689
GHSA Identifier GHSA-hcxc-wf8j-23hv
Severity MODERATE
CVSS v3.1 Base Score 6.8
CWE Classification CWE-287: Improper Authentication
Affected Product OpenFGA
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 6.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N).

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability None (A:N)

How to Fix CVE-2026-55689

To remediate this vulnerability, upgrade all affected OpenFGA dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

github.com/openfga/openfga fixed: 1.18.0 
Upgrade github.com/openfga/openfga to 1.18.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for github.com/openfga/openfga

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-55689, inspect your project dependencies for OpenFGA:

inspect dependencies for github.com/openfga/openfga

Analyze the terminal output to locate any version of OpenFGA in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.18.0), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-287: Improper Authentication, where when an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. In OpenFGA, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

## 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: 1. You run OpenFGA with `authn.method` set to `oidc`. 2. You configured `authn.oidc.issuer` but did **not** set `authn.oidc.audience` (`--authn-oidc-audience` / `OPENFGA_AUTHN_OIDC_AUDIENCE`). ## Fix 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 the `aud` claim is always validated. ## Acknowledgements OpenFGA would like to thank https://github.com/0xVijay for the report.

CVE-2026-55689 Affected OpenFGA Versions

1 component(s)
Fixed Versions:
1.18.0
Product / Package Ecosystem Affected Versions Fixed Version
github.com/openfga/openfga
golang/github.com/openfga/openfga
Go
< 1.18.0
1.18.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/openfga/openfga/security/advisories/GHSA-hcxc-wf8j-23hv
NVD — CVE-2026-55689 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-55689
Security Fix Commit FIX COMMIT
https://github.com/openfga/openfga/commit/44596773b2e62738720ef215bf7fa04352954271
OpenFGA Source Repository REPOSITORY
https://github.com/openfga/helm-ch
OpenFGA Release RELEASE
https://github.com/openfga/helm-charts/releases/tag/openfga-0.3.9
OpenFGA Source Repository REPOSITORY
https://github.com/openfga/openfga
OpenFGA Release RELEASE
https://github.com/openfga/openfga/releases/tag/v1.18.0

Frequently Asked Questions

What is CVE-2026-55689?
CVE-2026-55689 is a security vulnerability in OpenFGA involving OIDC audience validation skipped when --authn-oidc-audience is unset under CWE-287: Improper Authentication.
Which OpenFGA versions are affected?
Affected versions include releases prior to 1.18.0 across affected packages: github.com/openfga/openfga.
What version fixes CVE-2026-55689?
Upgrading to 1.18.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is github.com/openfga/openfga affected?
Yes, github.com/openfga/openfga is affected in releases prior to 1.18.0. Upgrade your dependency to 1.18.0 or later.
What is the CVSS score of CVE-2026-55689?
CVE-2026-55689 has a CVSS v3.1 base score of 6.8 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N.
What CWE is associated with CVE-2026-55689?
CVE-2026-55689 is classified under CWE-287: Improper Authentication (When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.).
How can I check Go dependencies for CVE-2026-55689?
Run the dependency tree command: 'inspect dependencies for github.com/openfga/openfga'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-hcxc-wf8j-23hv",
  "modified" : "2026-07-21T14:52:50Z",
  "published" : "2026-06-19T14:35:35Z",
  "aliases" : [ "CVE-2026-55689" ],
  "summary" : "OpenFGA: OIDC audience validation skipped when --authn-oidc-audience is unset",
  "details" : "## Description\n\nOpenFGA's OIDC authenticator skipped JWT audience (`aud`) validation when no audience was configured.\nIn deployments where one identity provider issues tokens for multiple services,\na token minted for an unrelated service could authenticate to OpenFGA.\n\n## Preconditions\n\nThis applies if the following preconditions are met:\n\n1. You run OpenFGA with `authn.method` set to `oidc`.\n2. You configured `authn.oidc.issuer` but did **not** set\n   `authn.oidc.audience` (`--authn-oidc-audience` / `OPENFGA_AUTHN_OIDC_AUDIENCE`).\n\n## Fix\n\nUpgrade to OpenFGA 1.18.0 or greater. OpenFGA now refuses to start in `oidc`\nmode unless both `authn.oidc.issuer` and `authn.oidc.audience` are set, and the\n`aud` claim is always validated.\n\n## Acknowledgements\n\nOpenFGA would like to thank https://github.com/0xVijay for the report.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/openfga/openfga"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.18.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 1.17.1"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/openfga/openfga/security/advisories/GHSA-hcxc-wf8j-23hv"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-55689"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/openfga/openfga/commit/44596773b2e62738720ef215bf7fa04352954271"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/openfga/helm-ch"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/openfga/helm-charts/releases/tag/openfga-0.3.9"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/openfga/openfga"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/openfga/openfga/releases/tag/v1.18.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-287" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-19T14:35:35Z",
    "nvd_published_at" : "2026-07-09T22:17:06Z"
  }
}