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.

Project Subscriptions

Vendors Products
Mantisbt Subscribe
Mantisbt Subscribe
Advisories
Source ID Title
Github GHSA Github GHSA GHSA-qj6w-v29q-4rgx MantisBT is Vulnerable to Stored XSS in Custom Field Textarea Values
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Wed, 20 May 2026 22:45:00 +0000

Type Values Removed Values Added
First Time appeared Mantisbt
Mantisbt mantisbt
Vendors & Products Mantisbt
Mantisbt mantisbt

Wed, 20 May 2026 21:45:00 +0000

Type Values Removed Values Added
Description 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.
Title MantisBT is Vulnerable to Stored XSS through Custom Field Textarea Values
Weaknesses CWE-79
References
Metrics cvssV3_1

{'score': 5.4, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N'}


Projects

Sign in to view the affected projects.

cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-05-20T21:11:02.341Z

Reserved: 2026-04-07T22:40:33.822Z

Link: CVE-2026-39960

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-05-20T22:16:36.563

Modified: 2026-05-20T22:16:36.563

Link: CVE-2026-39960

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-20T22:30:40Z

Weaknesses