CVE-2026-107124
Description
A flaw was found in the OIDC logout endpoint of the keycloak-services component, which handles user session termination in Red Hat Build of Keycloak. The issue occurs because the system sets a session cookie based on an unvalidated token hint before completing security checks. An attacker can use this flaw to fix a session ID in a victim's browser, allowing them to hijack the victim's subsequent login and gain full control over their account.
Statement
The Red Hat Product Security team has assessed the severity of this vulnerability as Important, given that it requires the victim to have no active session and be induced to visit a crafted URL within a specific timing window. Successful exploitation allows an attacker to achieve full account takeover of any user in the realm, including administrators. The vulnerability's root cause is the premature setting of session cookies before token validation and the reuse of authentication session IDs during login.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.4 | N/A | 6.4 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | High | N/A | High |
| Privileges Required | Low | N/A | Low |
| User Interaction | Required | N/A | Required |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N
cve.org: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N
Understanding the Weakness (CWE)
Access Control
Technical Impact: Gain Privileges or Assume Identity
Acknowledgements
Red Hat would like to thank Adam Korczynski (Ada Logics Ltd) and Anthropic for reporting this issue.
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