Description
A flaw was found in the first-broker-login flow of the Keycloak identity management service. When a user links a social identity provider account to their local account, the verification proof generated is not strictly bound to the specific upstream identity being verified. This allows an attacker with a different account on the same social provider to intercept the process and link their own account to the victim's local profile, gaining unauthorized access.
References3
Metrics
- CVSS 3.1
-
6.4
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N - EPSS — exploit probability
- 0% percentile: 26 · as of 8 November 2026
- CWE
- CWE-639
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.