CVE-2026-33548 MantisBT has Stored HTML Injection / XSS when displaying Tags in Timeline
Attackers can inject HTML or JavaScript via tag names in the timeline, potentially executing arbitrary code if CSP permits.
- 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-2026-33548?
CVE-2026-33548 is a high-severity cross-site scripting vulnerability in Mantisbt Mantisbt, published on 23 Mar 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. In version 2.28.0, improper escaping of tag names retrieved from History in Timeline (my_view_page.php) allows an attacker to inject HTML and, if CSP settings permit, achieve execution of arbitrary JavaScript, when displaying a tag that has been renamed or deleted. Version 2.28.1 contains a patch. Workarounds include editing offending History entries (using SQL) and wrapping `$this->tag_name` in a string_html_specialchars() call in IssueTagTimelineEvent::html().
Weakness: CWE-79
Which versions are affected by CVE-2026-33548?
2 open source packages ship an affected version, including mantisbt/mantisbt. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
mantisbt/mantisbt Packagist | From 2.28.0 | 2.28.2 |
mantisbt/mantisbt Packagist | From 2.28.0 | 2.28.2 |
Products include Mantisbt Mantisbt.
How do I fix CVE-2026-33548?
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-2026-33548 being exploited?
There is no known exploitation of CVE-2026-33548 in the wild and no public exploit code.
Other vulnerabilities in Mantisbt Mantisbt
- CVE-2019-15074 MantisBT allows cross-site scripting (XSS) via crafted filename
- CVE-2026-30849 MantisBT SOAP API has an authentication bypass vulnerability on MySQL
- CVE-2025-47776 MantisBT: Authentication bypass for some passwords due to PHP type juggling
- CVE-2017-7615 MantisBT allows arbitrary password reset
- CVE-2026-33517 MantisBT Vulnerable to Stored HTML Injection in Tag Delete Confirmation
Sources
Also known as GHSA-73vx-49mv-v8w5.