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Description

Mantis Bug Tracker (MantisBT) is an open source issue tracker. In versions 2.28.1 and below, given any pre-existing XSS / HTML injection vulnerability, an attacker can bypass the Content Security Policy's script-src directive by uploading a crafted attachment to any issue that, when accessed via the file_download.php link, will be downloaded with a valid JavaScript MIME type resulting in script execution. The uploaded payload must be sniffed as a valid JavaScript MIME type by PHP finfo (see file_create_finfo() API function). Non-JavaScript MIME types will not get imported in a <script> tag by the browser, due to response header X-Content-Type-Options being set to nosniff, which requires all imported JavaScript files to be a valid JavaScript MIME type. This issue has been fixed in version 2.28.2.

PUBLISHED Reserved 2026-04-14 | Published 2026-05-22 | Updated 2026-05-26 | Assigner GitHub_M




HIGH: 7.6CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N

Problem types

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CWE-358: Improperly Implemented Security Check for Standard

Product status

< 2.28.2
affected

References

github.com/...ntisbt/security/advisories/GHSA-9c3j-xm6v-j7j3

github.com/...ommit/9e3bee2e7b909f4e3596985892b8bc8bee9e0bfe

mantisbt.org/bugs/view.php?id=37016

cve.org (CVE-2026-40597)

nvd.nist.gov (CVE-2026-40597)

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