CVE-2026-44657

High

Published: 28 May 2026

Published

28 May 2026

Modified

29 May 2026

KEV Added

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Patch

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CVSS Score v4 7.5 CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Score 0.0035 26.6th percentile

Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-44657 is a high-severity Cross-site Scripting (CWE-79) vulnerability in Mantisbt (inferred from references). Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 26.6th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

No EU or UK CSIRT advisories indexed for this CVE.

Vulnerability details

Mantis Bug Tracker (MantisBT) is an open source issue tracker. Prior to 2.28.2, using show_inline=1 parameter and a valid file_show_inline_token CSRF token on file_download.php, an attacker can execute code by uploading a crafted XHTML attachment referencing a JavaScript attachment. This…

vulnerability is fixed in 2.28.2.

CWE(s): CWE-79

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

T1203 Exploitation for Client Execution Execution

Adversaries may exploit software vulnerabilities in client applications to execute code.

attack.mitre.org →

T1059.007 JavaScript Execution

Adversaries may abuse various implementations of JavaScript for execution.

attack.mitre.org →

Why these techniques?

Stored XSS via crafted XHTML/JS attachments on file_download.php directly enables client-side JS execution (T1059.007) after exploiting the public web app (T1190) for client execution (T1203).

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1