TI-2026-28816 Aliases CVE-2026-39960 GHSA-qj6w-v29q-4rgx

MantisBT is Vulnerable to Stored XSS through Custom Field Textarea Values

LOW 24CWE-79Published 2026-05-20 · Updated 2026-05-21

Key facts

Attack vector: Network
Privileges required: Low
User interaction: Required
Attack complexity: Low
Impact type: Cross-site scripting
Confidentiality · integrity · availability: Low · Low · None
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-79.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.0023 13th percentileScored 2026-11-07

Fix Fixed mantisbt (mantisbt): 2.28.2mantisbt/mantisbt (Packagist): 2.28.2

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
mantisbt	mantisbt	before 2.28.2	2.28.2	Patch available	CNA
—	mantisbt/mantisbt (Packagist)	before 2.28.2	2.28.2	Patch available	GHSA-qj6w-v29q-4rgx

mantisbt Vendormantisbt Affected before 2.28.2 Fixed in 2.28.2 Patch available CNA
mantisbt/mantisbt (Packagist) Vendor— Affected before 2.28.2 Fixed in 2.28.2 Patch available GHSA-qj6w-v29q-4rgx

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPE	Versions	Role	Vendor
cpe:2.3:a:mantisbt:mantisbt::::::::	—	—	mantisbt

cpe:2.3:a:mantisbt:mantisbt:*:*:*:*:*:*:*:* Versions — — ·mantisbt

Remediation

Fix · CNA mantisbt (mantisbt) Fixed in 2.28.2
Fix · GHSA-qj6w-v29q-4rgx mantisbt/mantisbt (Packagist) Fixed in 2.28.2 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2026-39960
2026-10-03 Alias added: GHSA-qj6w-v29q-4rgx

References

Advisory 1

https://nvd.nist.gov/vuln/detail/CVE-2026-39960

Other 4

TI-2017-05251 MantisBT through 2.3.0 allows arbitrary password reset and unauthenticated admin access… CVSS 3.1HIGH 8.8
TI-2026-29334 MantisBT has Potential Referer-Based Reflected HTML Injection / XSS in Tag Update Page CVSS 4.0MEDIUM 6.9
TI-2014-05966 The XmlImportExport plugin in MantisBT 1.2.17 and earlier allows remote attackers to… CVSS 2.0HIGH 7.5
TI-2026-27192 MantisBT Bugnote Revision Page Leaks Private Issue Metadata After Issue Access Is Revoked CVSS 4.0MEDIUM 5.3
TI-2026-25495 MantisBT: Authorization Bypass in Global Profile Creation CVSS 4.0MEDIUM 5.3
TI-2026-26676 MantisBT: Privilege Escalation from Manager to Administrator CVSS 4.0MEDIUM 5.1

See all 144 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences