CVE-2026-39960

mediumpriority · track · 0EPSS 0.002 · 14 %ileEUUS
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
0.23% (14th) EPSS
CVSS 5.4 · medium
Is it mine?
2 products
Check your exposure
Who says so?
3 sources
cnnvd · enisa_euvd · osv

EPSS · scored 2026-10-29

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.

01

cvss

Technical severity, 0–10. One row per scoring source.

5.4
010

base score 0–10 · higher = more severe · hover a vector to decode

v3.15.4mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:Nsecondary · ENISA EU
v3.15.4mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:Nsecondary · security-advisories@github.comexploitability 2.3 · impact 2.7
v3.15.4mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:Nsecondary · OSV
v3.15mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N/E:Usecondary · CVSS-BT (t0sche)
02

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS
03

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-79USCWE-79US
04

affected products (2)

Products and version ranges known to be affected.

05

advisories (1)

Vendor and ecosystem advisories describing this.

  • GHSA-qj6w-v29q-4rgxMantisBT is Vulnerable to Stored XSS in Custom Field Textarea Values2026-05-11ghsa · osvUS

    Improper escaping of a textarea custom field's contents in the Update Issue page (bug_update_page.php) allows an attacker to inject HTML and, if CSP settings permit, execute arbitrary JavaScript when the page is loaded. ### Impact Session theft leading to admin account takeover, full project data access. - Precondition: A textarea-type custom field must be configured for the project - Attacker: Authenticated user with bug report permission (low privilege) - Victim: Any user viewing the bug edit form, including administrators ### Patches - 5fec0f448b7a7d7d539a6adb6dccceac4e4e4ab7 ### Workarounds The default Content-Security Policy will block script execution. ### References - https://mantisbt.org/bugs/view.php?id=37003 - This is related to [CVE-2024-34081](https://github.com/advisories/GHSA-wgx7-jp56-65mq). ### Credits Thanks to the following security researchers for independently discovering and responsibly reporting the issue, and providing a patch to fix it. - Thanks to Nozomu Sasaki (Paul) (@morimori-dev) - Tristan Madani (@TristanInSec) from Talence Security

06

also known as (3)

Other names and identifiers for this entity.

07

sources

Which sources assert this record, and when.

cnnvdenisa_euvdosvNVDCVE.orgMITRE
published 2026-05-20modified 2026-07-23
08

references (6)

External citations — patches, advisories, analysis.

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