CVE-2026-90997 Keycloak - Authentication Bypass

Keycloak contains a replay protection bypass caused by row-count semantic mismatch in stateless mode with MySQL or MariaDB, letting attackers replay single-use security artifacts to gain unauthorized access, exploit requires stateless mode deployment.

CVSS base score 7.4 /10
High
CISA KEV
Not listed
Public exploit
None known
EPSS
0.40% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Authentication Bypass
Impact
Broken Authentication
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Published
17 September 2026
Updated
15 October 2026
Weakness
CWE-294

Vendor fix

Update to the latest Keycloak version with the fix for replay protection bypass.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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