6.5

CVE-2026-37979: redhat build_of_keycloak Improper Access Control

CVSS: 6.5v3.1MediumAnalyzed
AliasesCGA-59jj-3739-pj95CGA-fgmg-qqg6-qg8gCGA-hj2h-fgq9-xg95
Published 19-05-2026Last modified 20-05-2026
Open JSON

Vulnerability summary

CVE-2026-37979 is a medium (CVSS 6.5) Improper Access Control vulnerability in redhat build_of_keycloak. EPSS estimates a 0.41% chance of exploitation in the next 30 days, higher than 34.6% of scored vulnerabilities.

Overall risk
26/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.5/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.41%
0%100%
Low · +0.05 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 19-05-2026
    PublishedVulnerability first disclosed.
  2. 20-05-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

0.41%

Chance of exploitation in the next 30 days

Percentile

35%

Versus all other CVEs

30-day change

+0.05 pp

From 0.37% on 22-09-2026

22-09-202622-10-2026
EPSS score
0.41%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Chainguard12 products
  • keycloak-26.4All versions (No fix recorded)
  • keycloak-26.4-iamguarded-compatAll versions (No fix recorded)
  • keycloak-26.5All versions (No fix recorded)
  • keycloak-26.5-iamguarded-compatAll versions (No fix recorded)
  • keycloak-fips-26.4All versions (No fix recorded)
Wolfi4 products
  • keycloak-26.4All versions (No fix recorded)
  • keycloak-26.4-iamguarded-compatAll versions (No fix recorded)
  • keycloak-26.5All versions (No fix recorded)
  • keycloak-26.5-iamguarded-compatAll versions (No fix recorded)
Org.keycloak1 product
  • keycloak-services< 26.6.2
Redhat1 product

4 vendors · 18 products

References

8 links