Cross-site scripting in MantisBT - CVE-2026-33517
Published: November 6, 2026
Vulnerability identifier: #VU159792
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-2026-33517
CWE-ID: CWE-79
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote authenticated attacker with low privileges to inject stored HTML and execute arbitrary JavaScript in a victim's browser when Content Security Policy settings permit.
The vulnerability exists due to improper escaping of tag names in MantisBT's tag_delete.php when rendering the tag deletion confirmation. A remote authenticated attacker with low privileges can store a malicious tag name that executes script when a victim opens the deletion confirmation.
Affected software
MantisBT
How to mitigate CVE-2026-33517
Install security update from vendor's website.
MantisBT - update to 2.28.1