CVE-2026-39960
MediumCVSS 5.4Exploitation Probability (EPSS)
Low risk14th percentile - higher than 14% of all known CVEs
Summary
Mantis Bug Tracker (MantisBT) up to version 2.28.1 is vulnerable to HTML and JavaScript injection in a textarea custom field on the Update Issue page. An authenticated attacker with low privileges can inject code that executes in the administrator's browser, leading to session theft and account takeover.
Risk Assessment
An attacker can take over an admin account and gain full access to project data.
Recommendation
Update MantisBT to version 2.28.2 or apply the default CSP policy that blocks script execution.
Original NVD description (English source)
Mantis Bug Tracker (MantisBT) is an open source issue tracker. Versions 2.28.1 and below contain flawed logic that causes improper escaping of a textarea custom field's contents in the Update Issue page, (bug_update_page.php) allowing an attacker to inject HTML and, if CSP settings permit, execute arbitrary JavaScript when the page is loaded. This facilitates session theft, leading to admin account takeover, full project data access. In order to exploit this issue, a textarea-type custom field must be configured for the project, the attack must be carried out by an authenticated user with bug report permission (low privilege). This can affect any user viewing the bug edit form, including administrators. The issue has been fixed in version 2.28.2. If users cannot immediately upgrade, they can work around the issue by using the default Content-Security Policy, which blocks script execution.