Keycloak: cross-session email verification proof not bound to upstream identity in first-broker-login
13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 6.4epss 0.3%
exploitation probability
0.3%top 76% of all CVEs
observed exploitation
nono source reports it
A flaw was found in Keycloak. The cross-session verification proof is keyed only by (local userId,
idpAlias) and is not bound to the upstream identity that was actually verified, so a second upstream account on the same IdP can consume it and get linked to the victim's local account.
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N
Affected products
Red Hat · Red Hat build of Keycloak 26.4Red Hat · Red Hat build of Keycloak 26.4.13Red Hat · Red Hat build of Keycloak 26.6Red Hat · Red Hat build of Keycloak 26.6.3References
https://access.redhat.com/errata/RHSA-2026:25097https://access.redhat.com/errata/RHSA-2026:25098https://access.redhat.com/errata/RHSA-2026:30049https://access.redhat.com/errata/RHSA-2026:30050https://access.redhat.com/security/cve/CVE-2026-9087https://bugzilla.redhat.com/show_bug.cgi?id=2480172