Vulnerability · Published Sep 17, 2026 · Assigned by redhat

CVE-2026-90997Keycloak-services: keycloak: replay protection bypass leads to unauthorized access via database driver semantics mismatch

High 7.4

In plain English

A high-severity security flaw in Keycloak from Keycloak. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 34% of all known vulnerabilities).

Severity (CVSS 3.1)7.4High

Exploit odds (30 days)0.4%top 66.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

A flaw was found in Keycloak. When deployed in stateless mode with MySQL or MariaDB, a mismatch in row-count semantics between the database driver and Keycloak's application logic allows an attacker to bypass replay protection. This vulnerability enables an attacker who intercepts single-use security artifacts, such as JWT client assertions, DPoP proofs, or one-time password (TOTP) codes, to replay them. Successful exploitation grants unauthorized access to the token endpoint or login flow.

Affected products (as reported)

Vendor	Product	Versions
Keycloak	Keycloak	26.7.0 – before 26.7.4
Red Hat	Red Hat Build of Keycloak	see references
Red Hat	Red Hat Build of Keycloak	see references

Weakness: CWE-294 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

References

https://access.redhat.com/security/cve/CVE-2026-90997 vdb-entry, x_refsource_REDHAT
RHBZ#2533141 issue-tracking, x_refsource_REDHAT