Vulnerability · CVE-2026-39960
Mantis Bug Tracker (MantisBT) is an open source issue tracker.
Published May 20, 2026 · catalog updated Jul 23, 2026 · Mantis Bug Tracker (MantisBT)
Check if you run it
No confirmed exploitation is on record for CVE-2026-39960. EPSS is 0.29%. Act only if a listed version of Mantis Bug Tracker (MantisBT) is installed.
Gaps on this record
- The stored product name is a package slug. The name on this page is taken from the title (Mantis Bug Tracker (MantisBT)).
- No version range is stored. A customer cannot check an installed version against this record.
- No vendor fix or required action is stored. Compare the linked advisory before you change production.
- Severity
- Medium5.4
- Known exploitation
- Not in CISA/VulnCheck KEV
- EPSS
- 0.29%
- Remediation
- Advisory link
- Affected products
- See sources for product scope
Mantis Bug Tracker (MantisBT) is an open source issue tracker. Versions 2.28.1 and below contain flawed logic that causes improper escaping of a textarea custom field's contents in the Update Issue page, (bug_update_page.php) allowing an attacker to inject HTML and, if CSP settings permit, execute arbitrary JavaScript when the page is loaded. This facilitates session theft, leading to admin account takeover, full project data access. In order to exploit this issue, a textarea-type custom field must be configured for the project, the attack must be carried out by an authenticated user with bug report permission (low privilege). This can affect any user viewing the bug edit form, including administrators. The issue has been fixed in version 2.28.2. If users cannot immediately upgrade, they can work around the issue by using the default Content-Security Policy, which blocks script execution.
No affected version ranges are stored yet. Use the vendor advisory before you decide this record does not apply.
How to fix CVE-2026-39960
Recommended remediation
A patch or advisory reference is linked. Open the original publisher for availability by product version.
Official advisories
What to do
Three questions, each answered from this record only. Confirm the vendor advisory before you patch.
Should you patch?
No confirmed exploitation is on record for CVE-2026-39960. EPSS is 0.29%. Act only if a listed version of Mantis Bug Tracker (MantisBT) is installed.
Which versions are affected?
Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.
What should an analyst verify?
CWE-79: Cross-site Scripting (XSS). EPSS 0.29%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.
Code
The project this record applies to. Exploit listings stay in References.
Timeline
Detection, updates, and resolution for this record.
May 20, 2026 · NIST NVD
Detected
Mantis Bug Tracker (MantisBT) is an open source issue tracker. Versions 2.28.1 and below contain flawed logic that causes improper escaping of a textarea custom field's contents in the Update Issue page, (bug_update_page.php) allowing an attacker to inject HTML and, if CSP settings permit, execute arbitrary JavaScript when the page is loaded. This facilitates session theft, leading to admin accoun
Jul 23, 2026 · NIST NVD
Updated
Mantis Bug Tracker (MantisBT) is an open source issue tracker. Versions 2.28.1 and below contain flawed logic that causes improper escaping of a textarea custom field's contents in the Update Issue page, (bug_update_page.php) allowing an attacker to inject HTML and, if CSP settings permit, execute arbitrary JavaScript when the page is loaded. This facilitates session theft, leading to admin accoun
Sources
- CVE.orgVulnerability recordCVE-2026-39960
Official CVE identifier
cve.org - FIRST EPSSExploitation probabilityCVE-2026-39960
30-day exploitation probability 0.3%
first.org - NIST NVDVulnerability recordCVE-2026-39960
Mantis Bug Tracker (MantisBT) is an open source issue tracker. Versions 2.28.1 and below contain flawed logic that causes improper escaping of a textarea custom field's contents in the Update Issue page, (bug_update_page.php) allowing an attacker to inject HTML and, if CSP settin
nvd.nist.gov
References
Freshness
Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.