CVE-2026-40597Network attack vector

Script execution via trusted attachment MIME type

Published May 22, 2026 · Updated May 22, 2026

Cross-site scripting in MantisBT 2.28.1 and earlier allows remote authenticated users to execute JavaScript via crafted attachments. file_download.php serves uploaded content with the JavaScript MIME type detected by PHP finfo, letting existing HTML injection import it as a script despite CSP. Exploitation requires issue-attachment privileges, a separate XSS or HTML injection path, and a payload detected as JavaScript.

CVSS severity7.6
High
EPSS probability0.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in MantisBT 2.28.1 and earlier allows remote authenticated users to execute JavaScript via crafted attachments. file_download.php serves uploaded content with the JavaScript MIME type detected by PHP finfo, letting existing HTML injection import it as a script despite CSP. Exploitation requires issue-attachment privileges, a separate XSS or HTML injection path, and a payload detected as JavaScript.

The record

CVE
CVE-2026-40597
Published
May 22, 2026
Updated
May 22, 2026
Vendor
MantisBT
Product
MantisBT
Classifications
CWE-79, CWE-358, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 22, 2026CVE publishedPublication date reported by the CVE source.
  2. May 22, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 2.28.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

MantisBT · MantisBTversion=< 2.28.2

Published CVSS scores

7.6GitHubCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-358Improperly Implemented Security Check for Standard
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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