CVE-2026-40597CWE-358CWE-79

MantisBT has a Content Security Policy bypass via attachments

High · published May 22, 2026

CVSS v4.0
7.6
EPSS
1%
Percentile
47.4
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
7.6 · HIGH
Vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N
EPSS
0.00587 · 47.4th percentile
Weaknesses
CWE-358 · Improperly Implemented Security Check for Standard; CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Published
2026-05-22T19:29Z
EPSS history
Timeline
  • 22 MAY 19:29Z
    MantisBT has a Content Security Policy bypass via attachments
    cvelistv5