CVE-2026-44657 MantisBT: Stored XSS in File Download
An attacker can execute arbitrary code via stored XSS by uploading crafted XHTML attachments in MantisBT.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-44657?
CVE-2026-44657 is a high-severity cross-site scripting vulnerability in mantisbt, published on 28 May 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
Mantis Bug Tracker (MantisBT) is an open source issue tracker. Prior to 2.28.2, using show_inline=1 parameter and a valid file_show_inline_token CSRF token on file_download.php, an attacker can execute code by uploading a crafted XHTML attachment referencing a JavaScript attachment. This vulnerability is fixed in 2.28.2.
Weakness: CWE-79
Which versions are affected by CVE-2026-44657?
2 open source packages ship an affected version, including mantisbt/mantisbt.
| Package | Affected | Fixed in |
|---|---|---|
mantisbt/mantisbt Packagist | All versions | 2.28.2 |
mantisbt/mantisbt Packagist | All versions | 2.28.2 |
How do I fix CVE-2026-44657?
Upgrade mantisbt/mantisbt to 2.28.2 or later.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-44657 being exploited?
There is no known exploitation of CVE-2026-44657 in the wild and no public exploit code.
Sources
Also known as GHSA-p6fr-rxq7-xcg8.