MantisBT Vulnerable to Stored XSS in File Download — CVE-2026-44657

Summary

Using *show_inline=1* parameter and a valid *file_show_inline_token* CSRF token on file_download.php, an attacker can execute code by uploading a crafted XHTML attachment referencing a JavaScript attachment. ### Impact Cross-site scripting ### Patches - 26647b2e68ba30b9d7987d4e03d7a16416684bc2 ### Workarounds None ### Credits Thanks to siunam (Tang Cheuk Hei) for discovering and responsibly reporting the issue.

Product

composer: mantisbt/mantisbt

What to do

General, cautious steps (verify details in the official source):

• Prioritize patching or mitigation immediately (treat as actively risky).
• Identify affected product versions in your inventory and verify whether you are impacted.
• Apply vendor patches/updates or recommended mitigations as soon as available.
• Read the official advisory for exact affected versions and remediation steps.

Official advisory

• Read the official source
• CVE Record
• NVD

Related advisories