CVE-2026-55867 Graylog token revocation endpoint allows authenticated users to delete other users’ access tokens

What is CVE-2026-55867?

CVE-2026-55867 is a medium-severity missing authorization vulnerability in graylog2-server, published on 28 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

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.

Weakness: CWE-639

Which versions are affected by CVE-2026-55867?

6 open source packages ship an affected version, including org.graylog2:graylog2-server.

How do I fix CVE-2026-55867?

Upgrade org.graylog2:graylog2-server to a fixed version for your release line: 6.3.12, 7.0.7 or 7.1.2.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2026-55867 being exploited?

There is no known exploitation of CVE-2026-55867 in the wild and no public exploit code.

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-j769-9gv9-65gr.