Description
A flaw was found in the User-Managed Access (UMA) implementation of Keycloak. The issue occurs in the authorization token endpoint when processing permission tickets. If two different users own resources with the same name, the system incorrectly merges the permissions from both resources when one user requests an authorization token. This allows an attacker to gain access scopes on a victim's resource that were never intended to be shared.
References3
Metrics
- CVSS 3.1
-
3.5
LOW
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N - EPSS — exploit probability
- 0% percentile: 22 · as of 8 November 2026
- CWE
- CWE-862
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.