Auth bypass in Graylog2 Graylog2-Server

CVE-2026-55867

Graylog is a free and open log management platform. From 6.2.0 until 6.3.12, 7.0.7, and 7.1.2, the DELETE /users/{userId}/tokens/{idOrToken} endpoint implemented by UsersResource.revokeToken() in graylog2-server/src/main/java/org/graylog2/rest/resources/users/UsersResource.java checks USERS_TOKENREMOVE permission against the attacker-controlled userId path parameter before resolving the token selected by idOrToken. An authenticated user can provide an authorized userId while accessTokenService.loadById() or accessTokenService.load() resolves a token belonging to another user, including a service account or administrator, after which accessTokenService.destroy() deletes that token without checking AccessToken.getUserName(). The issue does not expose token contents, but unauthorized deletion causes integrity impact and can disrupt access-token-based integrations. This issue is fixed in versions 6.3.12, 7.0.7, and 7.1.2.

Vulnerability class: IDOR (Insecure Direct Object Reference)

Published 2026-08-28 · last modified 2026-09-09.