CVE-2026-34579 MEDIUM

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

Vendor Mantisbt
Product mantisbt
Weakness CWE-863 · Incorrect authorization
Published May 19, 2026
Last update May 20, 2026

CVSS base score

5.3/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

What the vulnerability does

01Description

Mantis Bug Tracker (MantisBT) is an open source issue tracker. Versions 2.28.1 and prior are vulnerable to Authorization Bypass through the private issue monitoring feature . 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. Direct access to the private issue remains blocked, but the user will receive email notifications for updates, leading to disclosure of the private issue's metadata and content. This issue has been fixed in version 2.28.2.

Key dates

02Disclosure timeline

May 19, 2026 CVE published
May 20, 2026 Record updated