CVE-2026-37979
Keycloak: keycloak: information disclosure via oidc token introspection endpoint audience bypass
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
6.5
Keycloak: keycloak: information disclosure via oidc token introspection endpoint audience bypass
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.
- Record
CVE-2026-37979- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-639, CWE-284
- Updated
- 2026-11-02
EUVDEUVD-2026-30887
6.5
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.
- Record
EUVD-2026-30887- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-4x37-hw65-52w8
6.5
Keycloak: Information disclosure via OIDC token introspection endpoint audience bypass
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.
- Record
GHSA-4x37-hw65-52w8- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-284
- Updated
- 2026-11-02
NVD
6.5
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.
- Record
CVE-2026-37979- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-639, CWE-284
- Updated
- 2026-11-02
OSVGHSA-4x37-hw65-52w8
6.5
Keycloak: Information disclosure via OIDC token introspection endpoint audience bypass
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.
- Record
GHSA-4x37-hw65-52w8- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-284
- Updated
- 2026-11-02
OSVBIT-keycloak-2026-37979 No score
Keycloak: keycloak: information disclosure via oidc token introspection endpoint audience bypass
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.
- Record
BIT-keycloak-2026-37979- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
org.keycloak:keycloak-servicesMaven |
before 26.6.2 | 26.6.2 |
keycloakBitnami |
26.4.0 up to 26.4.12 | 26.4.12 |
org.keycloak:keycloak-servicesMaven |
before 26.6.2, plus listed versions 1.0-alpha-11.0-alpha-1-120620131.0-alpha-21.0-alpha-31.0-alpha-4 Show 45 moreShow less1.0-beta-11.0-beta-1-201505211.0-beta-1-201505231.0-beta-21.0-beta-31.0-beta-41.0-final1.0-rc-11.0-rc-21.0.1.Final1.0.2.Final1.0.3.Final1.0.4.Final1.0.5.Final1.1.0.Beta11.1.0.Beta21.1.0.Final1.1.1.Final1.2.0.Beta11.2.0.CR11.2.0.Final1.3.0.Final1.3.1.Final1.4.0.Final1.5.0-Final1.5.0.Final1.5.1.Final1.6.0.Final1.6.1.Final1.7.0.CR11.7.0.Final1.8.0.Alpha11.8.0.CR11.8.0.CR21.8.0.CR31.8.0.Final1.8.1.Final1.9.0.CR11.9.0.Final1.9.1.Final1.9.2.Final1.9.3.Final1.9.4.Final1.9.5.Final1.9.7.Final |
26.6.2 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-37979 is a medium vulnerability (CVSS 6.5) in Red Hat Build Of Keycloak 26.4, published May 19, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.37%, the 30th percentile. Fixed in org.keycloak:keycloak-services 26.6.2.
References
access.redhat.com/errata/RHSA-2026:19596
access.redhat.com/errata/RHSA-2026:19597
access.redhat.com/security/cve/CVE-2026-37979
bugzilla.redhat.com/show_bug.cgi?id=2455328
nvd.nist.gov/vuln/detail/CVE-2026-37979
github.com/keycloak/keycloak/issues/49113
github.com/keycloak/keycloak/releases/tag/26.6.2
github.com/advisories/GHSA-4x37-hw65-52w8
github.com/keycloak/keycloak
Left out here: 176 versions. The JSON record has them.