Summary
MantisBT: Reflected XSS in admin/install.php
MantisBT 2.28.3 and earlier contains six reflected XSS injection points in /admin/install.php. User-supplied parameters are echoed into HTML without escaping via print_test_result(). No authentication is required.
A Content Security Policy (script-src 'self') prevents inline JavaScript execution, but the CSP is missing a form-action directive, allowing exploitation via credential-phishing form injection and open redirects.
Workarounds
Remove the /admin directory, as recommended in the Admin Guide
Resources
- https://mantisbt.org/bugs/view.php?id=37103
- related advisory GHSA-vcrw-4xvv-jh49
Credits
McCaulay Hudson (@_McCaulay) of watchTowr
Impact
- Credential phishing: Attacker crafts a URL that renders a fake login form on the real MantisBT admin page. Admin credentials are submitted to an attacker-controlled server.
- Open redirect: Victim is silently redirected to a phishing or malware site.
- UI manipulation: CSS injection can hide legitimate page content and overlay attacker-controlled HTML, enabling social engineering.
Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2026-52847? CVE-2026-52847 is a critical-severity cross-site scripting (XSS) vulnerability in mantisbt/mantisbt (composer), affecting versions <= 2.28.3. It is fixed in 2.28.4. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
- Which versions of mantisbt/mantisbt are affected by CVE-2026-52847? mantisbt/mantisbt (composer) versions <= 2.28.3 is affected.
- Is there a fix for CVE-2026-52847? Yes. CVE-2026-52847 is fixed in 2.28.4. Upgrade to this version or later.
- Is CVE-2026-52847 exploitable, and should I be worried? Whether CVE-2026-52847 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-52847 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-52847? Upgrade
mantisbt/mantisbtto 2.28.4 or later.