CVE-2026-117859: Keycloak-services: keycloak-services: par single-use bypass via flow restart

Severity: medium (CVSS 5.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-29 · updated 2026-10-29
Weakness: CWE-670

Description

A flaw was found in the Pushed Authorization Request PAR implementation of the keycloak-services component. The issue occurs when an authentication flow is restarted, which incorrectly clears the internal markers used to track PAR consumption while leaving the request active. This allows an attacker to reuse the same authorization request to obtain multiple access tokens, bypassing security requirements for single-use requests.

Affected products

Red Hat build of Keycloak 26.4: all versions

References

https://access.redhat.com/security/cve/CVE-2026-117859
https://bugzilla.redhat.com/show_bug.cgi?id=2561991

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