CVE-2026-74909: Keycloak-services: keycloak-services: incomplete fix for cve-2026-15573 allows policy enforcer bypass via percent-encoded uri segments

Severity: high (CVSS 8.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.8% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-16 · updated 2026-09-18
Weakness: CWE-862

Description

Keycloak provides a policy enforcer to protect applications by matching incoming web requests against defined security policies. A flaw was found where the enforcer fails to correctly normalize web addresses that contain special encoded characters, such as those representing semicolons or directory traversal segments. An authenticated user can use these encoded characters to trick the enforcer into applying a less restrictive security policy than intended, potentially gaining unauthorized access to sensitive administrative or private application endpoints.

Affected products

Red Hat build of Keycloak 26.4: all versions — fixed in 26.4-26, 26.4.16-2, 26.6-20, 26.6.7-3

How to fix

Upgrade to a fixed version: Red Hat build of Keycloak 26.4 26.4-26, 26.4.16-2, 26.6-20, 26.6.7-3. Check the vendor advisory for mitigations.

References

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