# CVE-2026-40597

## Summary

- **CVE ID:** CVE-2026-40597
- **Severity:** HIGH
- **CVSS Score:** 7.6 (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)
- **CWE:** CWE-79, CWE-358
- **Published:** May 22, 2026
- **Last Modified:** May 26, 2026

## 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.

## Affected Products

- mantisbt — mantisbt (< 2.28.2)

## References

- [CNA](https://github.com/mantisbt/mantisbt/security/advisories/GHSA-9c3j-xm6v-j7j3)
- [CNA](https://github.com/mantisbt/mantisbt/commit/9e3bee2e7b909f4e3596985892b8bc8bee9e0bfe)
- [CNA](https://mantisbt.org/bugs/view.php?id=37016)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.50%
- **EPSS Percentile:** 41.1

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._