MantisBT: Authorization Bypass in Bugnote Editing via Issue Update API

The mc_issue_update() function in MantisBT allows users having update_bug_threshold access (UPDATER, with default settings) to edit, change view state, and modify time tracking on bugnotes belonging to other users — bypassing the default DEVELOPER (level 55) threshold required by the dedicated mc_issue_note_update() function.

Impact

1. UPDATER can edit notes by DEVELOPER/MANAGER/ADMIN — bypassing the DEVELOPER threshold
2. UPDATER can change private notes to public — exposing confidential internal discussion
3. UPDATER can change public notes to private — hiding information from reporters/viewers

Patches

• 6e58fae4f22efdc3987f903c8ba2611de17a9435

Workarounds

None

Credits

Thanks to the following security researchers for independently discovering and responsibly reporting the issue.

• Vishal Shukla
• Tristan Madani (@TristanInSec) from Talence Security

This advisory's contents was largely copied from Tristan's well-written report.