How severe is CVE-2026-37979?

CVE-2026-37979 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2026-37979 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (30th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-37979?

CVE-2026-37979 affects Redhat Build Of Keycloak. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-37979?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-37979 have an EU (EUVD) identifier?

Yes. CVE-2026-37979 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-30887.

When was CVE-2026-37979 published?

CVE-2026-37979 was published on 2026-05-19 and last updated on 2026-06-17.

CVE-2026-37979

CVE-2026-37979 is a medium-severity vulnerability in Redhat Build Of Keycloak with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-284.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
EPSS exploit prediction: 0% (30th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-30887
Weakness: CWE-284
Affected product: Redhat Build Of Keycloak
Published: 2026-05-19
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-37979?: 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.
How severe is CVE-2026-37979?: CVE-2026-37979 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2026-37979 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (30th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-37979?: CVE-2026-37979 affects Redhat Build Of Keycloak. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-37979?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-37979 have an EU (EUVD) identifier?: Yes. CVE-2026-37979 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-30887.
When was CVE-2026-37979 published?: CVE-2026-37979 was published on 2026-05-19 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:redhat:build_of_keycloak:*:*:*:*:*:*:*:*

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