CVE-2026-37979 Keycloak: keycloak: information disclosure via oidc token introspection endpoint audience bypass
A confidential client can bypass audience restrictions in Keycloak's OIDC token introspection endpoint to retrieve sensitive token claims intended for other resource servers.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-37979?
CVE-2026-37979 is a medium-severity vulnerability in Redhat Build of Keycloak, published on 19 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
A flaw was found in Keycloak. This access control vulnerability in Keycloak's OpenID Connect (OIDC) token introspection endpoint allows a confidential client to bypass audience restrictions. An attacker-controlled client with valid credentials can retrieve sensitive token claims intended for other resource servers, compromising the confidentiality of lightweight access tokens. This issue can be exploited remotely by any confidential client in the realm with valid credentials.
Which versions are affected by CVE-2026-37979?
3 open source packages ship an affected version, including org.keycloak:keycloak-services and keycloak. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
org.keycloak:keycloak-services Maven | All versions | 26.6.2 |
org.keycloak:keycloak-services Maven | All versions | 26.6.2 |
keycloak Bitnami | From 26.4.0 | 26.4.12 |
Products include Redhat Build of Keycloak.
How do I fix CVE-2026-37979?
Upgrade org.keycloak:keycloak-services to 26.6.2 or later.
Is CVE-2026-37979 being exploited?
There is no known exploitation of CVE-2026-37979 in the wild and no public exploit code.
Other vulnerabilities in Redhat Build of Keycloak
- CVE-2026-15572 Keycloak-services: keycloak-services: dcr protocol mapper type-swap policy bypass allows privilege escalation
- CVE-2026-3047 Keycloak SAML Broken has Authentication Bypass by Primary Weakness
- CVE-2026-15573 Keycloak-services: keycloak-services: authorization bypass via unnormalized uri matching in pathmatcher
- CVE-2026-16102 Keycloak-services: keycloak-services: default dcr policy allows role forgery via user property mappers
- CVE-2026-1609 Org.keycloak/keycloak-quarkus-server: keycloak: unauthorized access via jwt authorization grant with disabled users
Sources
Also known as BIT-keycloak-2026-37979, ECHO-b09d-c689-b716, GHSA-4x37-hw65-52w8, MINI-4c54-7r6w-253c, MINI-8qcv-j2cw-88m2.