Description
A session fixation vulnerability was found in Keycloak's login-actions endpoints. An unauthenticated attacker could exploit this flaw by pre-creating an authentication session and tricking a victim into visiting a maliciously crafted link. By leveraging the /login-actions/restart endpoint—which processes session handles without adequate CSRF protection or cookie ownership validation—an attacker can reset the authentication flow state. This causes Single Sign-On (SSO) to authenticate the victim transparently upon clicking the link, allowing the attacker to hijack the required-action form without needing the victim's credentials. A successful exploit could lead to complete account takeover, including highly privileged administrative accounts.
CVSS breakdown
Affected products
- RedHat / build_of_keycloak26.4 – 26.4.12
References
- VENDOR_ADVISORYhttps://access.redhat.com/errata/RHSA-2026:19594
- VENDOR_ADVISORYhttps://access.redhat.com/errata/RHSA-2026:19595
- VENDOR_ADVISORYhttps://access.redhat.com/errata/RHSA-2026:19596
- VENDOR_ADVISORYhttps://access.redhat.com/errata/RHSA-2026:19597
- VENDOR_ADVISORYhttps://access.redhat.com/security/cve/CVE-2026-7507
- MISChttps://bugzilla.redhat.com/show_bug.cgi?id=2464145