CVE-2026-9087 — MEDIUM (6.4)

Vulnerability Description

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 Score

6.4

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N

Attack Vector

NETWORK

Attack Complexity

HIGH

Privileges Required

LOW

User Interaction

REQUIRED

Scope

UNCHANGED

Confidentiality

HIGH

Integrity

HIGH

Availability

NONE

Related Weaknesses (CWE)

CWE-639

References

FAQ

What is CVE-2026-9087?

CVE-2026-9087 is a vulnerability with a CVSS score of 6.4 (MEDIUM). 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 ...

How severe is CVE-2026-9087?

CVE-2026-9087 has been rated MEDIUM with a CVSS base score of 6.4/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-9087?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.