Improper escaping of a custom field's name allows an attacker to inject HTML and, if CSP settings permit, achieve execution of arbitrary JavaScript when:

• resolving or closing issues (bug_change_status_page.php) belonging to a project linking said custom field
• viewing issues (view_all_bug_page.php) when the custom field is displayed as a column
• printing issues (print_all_bug_page.php) when the custom field is displayed as a column

Impact

Cross-site scripting (XSS).

Patches

447a521

Workarounds

Ensure Custom Field Names do not contain HTML tags.

References

• https://mantisbt.org/bugs/view.php?id=34432
• This is related to CVE-2020-25830 (same root cause, different affected pages)