BaseFortify

Publication date: 2025-10-28

Last updated on: 2025-11-28

Assigner: Red Hat, Inc.

Description

A flaw was found in Keycloak. In Keycloak where a user can accidentally get access to another user's session if both use the same device and browser. This happens because Keycloak sometimes reuses session identifiers and doesn’t clean up properly during logout when browser cookies are missing. As a result, one user may receive tokens that belong to another user.

CVSS Scores

EPSS Scores

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Meta Information

Published

2025-10-28

Last Modified

2025-11-28

Generated

2026-07-06

AI Q&A

2025-10-28

EPSS Evaluated

2026-07-05

NVD

CVE-2025-12390

Affected Vendors & Products

Vendor	Product	Version / Range
redhat	keycloak	26.4.4

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-384	Authenticating a user, or otherwise establishing a new user session, without invalidating any existing session identifier gives an attacker the opportunity to steal authenticated sessions.

Attack-Flow Graph

Executive Summary

This vulnerability in Keycloak allows a user to accidentally gain access to another user's session if both users use the same device and browser. The issue occurs because Keycloak sometimes reuses session identifiers and fails to properly clean up during logout when browser cookies are missing. Consequently, one user may receive authentication tokens that belong to another user.

Impact Analysis

This vulnerability can lead to unauthorized access to another user's session and sensitive information, potentially allowing one user to impersonate another. This can result in data breaches, loss of confidentiality, and unauthorized actions performed under another user's identity.

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