MantisBT Vulnerable to Denial-of-Service (DoS) via Excessive Note Length

A lack of server-side validation for note length in MantisBT allows attackers to permanently corrupt issue activity logs by submitting extremely long notes (tested with 4,788,761 characters). Once such a note is added:

Impact

• The entire activity stream becomes unviewable (UI fails to render).
• New notes cannot be displayed, effectively breaking all future collaboration on the issue.

Patches

Fixed in 2.27.2.

Workarounds

None

Credits

Thanks to Mazen Mahmoud (@TheAmazeng) for reporting the vulnerability.