Description
A flaw was found in the first broker login flow of Keycloak. When a user confirms an account-linking request from a different browser, a temporary proof is created to validate the link. However, this proof is not properly cleared after the link is established or when the user later manually removes the link. An attacker who controls the external identity can exploit this leftover proof to silently re-establish the link and gain unauthorized access to the victims account without any further confirmation.
References2
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: 23 · as of 7 November 2026
- CWE
- CWE-613
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.