Cross-site scripting in MantisBT - CVE-2026-44657
Published: November 6, 2026
Vulnerability identifier: #VU159794
CSH Severity: Low
CVSS v4: 5.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N]
CVE-ID: CVE-2026-44657
CWE-ID: CWE-79
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows an authenticated remote attacker to execute JavaScript in a victim's browser through stored cross-site scripting in MantisBT.
The vulnerability exists due to unsafe inline rendering of uploaded XHTML attachments by file_download.php when show_inline=1 and a valid file_show_inline_token CSRF token are supplied. An authenticated remote attacker can upload crafted XHTML referencing an uploaded JavaScript attachment and induce a victim to view it inline, triggering script execution.
Affected software
MantisBT
How to mitigate CVE-2026-44657
Install security update from vendor's website.
MantisBT - update to 2.28.2