CVE-2026-33548 — mantisbt/mantisbt
Fix: mantisbt/mantisbt@f32787cCVE-2026-33548 is a Cross-site Scripting (XSS) vulnerability in mantisbt/mantisbt. A fix is available for mantisbt/mantisbt — see the affected versions and patch details below.
MantisBT has Stored HTML Injection / XSS when displaying Tags in Timeline
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-33548.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
mantisbt/mantisbtReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
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.
Impact
Cross-site scripting (XSS).
Patches
f32787c14d4518476fe7f05f992dbfe6eaccd815
Workarounds
- Edit offending History entries (using SQL)
- Wrap
$this->tag_namein a string_html_specialchars() call in IssueTagTimelineEvent::html()
Credits
MantisBT thanks Vishal Shukla for discovering and responsibly reporting the issue.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | mantisbt/mantisbt | ≥ 2.28.0&&< 2.28.2 | 2.28.2composer require mantisbt/mantisbt:^2.28.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mantisbt/mantisbt, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update mantisbt/mantisbt to 2.28.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-33548 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-33548 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-33548. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-33548 in your dependencies?
O3 Security finds CVE-2026-33548 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.