CVE-2026-40598Network attack vector

Cross-site scripting via unescaped Referer redirect

Published May 22, 2026 · Updated May 22, 2026

Cross-site scripting in MantisBT 2.28.1 and earlier allows remote attackers to inject HTML through the Referer header on the tag update page. The tag_update_page.php template writes t_redirect_page, derived from Referer, into a hidden redirect input value without HTML escaping. Exploitation requires a server or cache configuration that preserves hostile Referer characters and passive user interaction; the consequence is attacker-controlled script execution within the MantisBT origin in a user's browser.

CVSS severity5.3
Medium
EPSS probability0.45%
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 attackers to inject HTML through the Referer header on the tag update page. The tag_update_page.php template writes t_redirect_page, derived from Referer, into a hidden redirect input value without HTML escaping. Exploitation requires a server or cache configuration that preserves hostile Referer characters and passive user interaction; the consequence is attacker-controlled script execution within the MantisBT origin in a user's browser.

The record

CVE
CVE-2026-40598
Published
May 22, 2026
Updated
May 22, 2026
Vendor
MantisBT
Product
MantisBT
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

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 privilegesunauthenticated

What is affected?

MantisBT · MantisBTversion=< 2.28.2

Published CVSS scores

5.3GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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