CVE-2026-34579: MantisBT has an authorization bypass in private issue monitoring

May 11, 2026 (updated June 5, 2026)

Using a crafted POST request to bug_monitor_add.php, a user with project-level access can add themselves as a monitor for a private issue they do not have access to. Despite displaying an Access Denied error, the application accepts the request and creates a monitor relationship for the private issue.

References

github.com/advisories/GHSA-ggw7-9675-6v4v
github.com/mantisbt/mantisbt/commit/0a93267deba445fb9d15250c16e6fdb1246ffa65
github.com/mantisbt/mantisbt/security/advisories/GHSA-ggw7-9675-6v4v
mantisbt.org/bugs/view.php?id=36975
nvd.nist.gov/vuln/detail/CVE-2026-34579

Code Behaviors & Features

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