CVE-2026-9087

Name: CVE-2026-9087
Creator: NVD / NIST
Published: 2026-05-20T17:16:32.207+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.1/10EPSS 0.31%

Last modified Jun 26, 2026

CVE-2026-9087 is a high-severity vulnerability rated 8.1/10 on the CVSS scale. 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.. EPSS estimates a 0.31% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

8.1/10

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

EPSS Probability

0.31%

22.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-639

Affected Software

Vendor	Product	Versions
Redhat	Build Of Keycloak	All versions

References

Timeline

Published: May 20, 2026
Last Modified: Jun 26, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2026-9087?

How severe is CVE-2026-9087?

CVE-2026-9087 has a CVSS score of 8.1/10 (HIGH severity). The EPSS model estimates a 0.31% probability of exploitation in the next 30 days.

How do I fix CVE-2026-9087?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-9087?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST