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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-90997
StatePUBLISHED
Assignerredhat
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-17 19:17:06 UTC
Updated2026-09-22 19:16:56 UTC
DescriptionA 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.

Risk And Classification

Primary CVSS: v3.1 7.4 HIGH from [email protected]

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

EPSS: 0.003960000 probability, percentile 0.336920000 (date 2026-09-23)

Problem Types: CWE-294 | CWE-294 Authentication Bypass by Capture-replay

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.4HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
3.1CNACVSS7.4HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Keycloak Keycloak affected 26.7.0 26.7.4 semver Not specified
CNA Red Hat Red Hat Build Of Keycloak Not specified Not specified
CNA Red Hat Red Hat Build Of Keycloak Not specified Not specified

References

ReferenceSourceLinkTags
access.redhat.com/security/cve/CVE-2026-90997 [email protected] access.redhat.com
bugzilla.redhat.com/show_bug.cgi [email protected] bugzilla.redhat.com
https://access.redhat.com/security/cve/CVE-2026-90997 MITRE access.redhat.com
github.com/keycloak/keycloak MITRE github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Additional Advisory Data

SourceTimeEvent
CNA2026-09-14T14:53:20.409ZReported to Red Hat.
CNA2026-09-16T14:21:23.000ZMade public.

Workarounds

CNA: To mitigate this issue, configure the JDBC connection string for MySQL/MariaDB to explicitly set `useAffectedRows=true`. This ensures the database driver correctly reports affected rows, preventing the replay protection bypass. This mitigation is applicable only when Keycloak is deployed in stateless mode and utilizes MySQL or MariaDB as its database. A restart of the Keycloak service will be required for the configuration change to take effect.

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