CVE-2026-33517: MantisBT Vulnerable to Stored HTML Injection in Tag Delete Confirmation
Improper escaping of Tag name when deleting it in tagdelete.php allows an attacker to inject HTML and, if CSP settings permit, achieve execution of arbitrary JavaScript.
Impact Cross-site scripting (XSS).
Patches 80990f43153167c73f11eb4b2bc7108d0c3d6b46
Workarounds Revert commit d6890320752ecf37bd74d11fe14fe7dc12335be9 Manually edit language files to remove the sprintf placeholder %1$s from $stagdeletemessage string, for example with sed -r -i '/tagdeletemessage/s/.%1\$s.//' -- lang/
Credits MantisBT hanks Vishal Shukla for discovering and responsibly reporting the issue.
Other sources
Mantis Bug Tracker (MantisBT) is an open source issue tracker. In version 2.28.0, when deleting a Tag (tagdelete.php), improper escaping of its name when displaying the confirmation message allows an attacker to inject HTML and, if CSP settings permit, achieve execution of arbitrary JavaScript. Version 2.28.1 fixes the issue. Workarounds include reverting commit d6890320752ecf37bd74d11fe14fe7dc12335be9 and/or manually editing language files to remove the sprintf placeholder %1$s from $stagdeletemessage string.
— MITRE
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2026-33517?
CVE-2026-33517 is considered a moderate severity vulnerability due to the potential for stored HTML injection.
How do I fix CVE-2026-33517?
To fix CVE-2026-33517, upgrade MantisBT to version 2.28.1 or later where the escaping issues have been addressed.
What software versions are affected by CVE-2026-33517?
CVE-2026-33517 affects MantisBT version 2.28.0.
What type of vulnerability is CVE-2026-33517?
CVE-2026-33517 is classified as a stored HTML injection vulnerability.
Can CVE-2026-33517 be exploited remotely?
Yes, CVE-2026-33517 can be exploited remotely, allowing attackers to inject malicious HTML into the web application.