CVE-2026-107889: medium-severity vulnerability in Red Hat Build of Keycloak
Keycloak-services: keycloak-services: stored xss on login page via kcsanitize bypass
Published · Updated
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13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.5epss 0.3%
A flaw was found in the login theme rendering component of Keycloak. The issue occurs because the security filter responsible for cleaning user input can be bypassed, allowing a realm administrator to store malicious scripts in display fields. This could result in unauthorized JavaScript execution in the browsers of users visiting the login page, potentially leading to data exposure or session interference.
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N
Related CVEs — Red Hat Build of Keycloak
In the same product, most dangerous first.
CVE-2026-18963CRITICALKeycloak-services: keycloak-services: unauthenticated account takeover via reset-credentials flow bypassEPSS 4.7%CVE-2024-1635HIGHUndertow: out-of-memory error after several closed connections with wildfly-http-client protocolEPSS 4.6%CVE-2023-5685HIGHXnio: stackoverflowexception when the chain of notifier states becomes problematically bigEPSS 3.5%CVE-2024-3656HIGHKeycloak: unguarded admin rest api endpoints allows low privilege users to use administrative functionalitiesEPSS 3.3%CVE-2024-5971HIGHUndertow: response write hangs in case of java 17 tlsv1.3 newsessionticketEPSS 2.9%CVE-2024-7885HIGHUndertow: improper state management in proxy protocol parsing causes information leakageEPSS 2.6%