CVE-2026-9087

EUVD-2026-31134
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.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
6.4 MEDIUM
NETWORK
HIGH
LOW
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: 22%
Affected Products (NVD)
VendorProductVersion
redhatbuild_of_keycloak
-
𝑥
= Vulnerable software versions
Common Weakness Enumeration
References
https://access.redhat.com/errata/RHSA-2026:25097
https://access.redhat.com/errata/RHSA-2026:25098
https://access.redhat.com/errata/RHSA-2026:30049
https://access.redhat.com/errata/RHSA-2026:30050
https://access.redhat.com/security/cve/CVE-2026-9087
https://bugzilla.redhat.com/show_bug.cgi?id=2480172