CVE-2025-53500Public exploitNetwork attack vector

Stored script execution via unescaped system messages

Published Jul 3, 2025 · Updated Jul 10, 2025

Stored XSS in Wikimedia Foundation MassEditRegex before 1.39.13, 1.42.7, and 1.43.2 allows remote authenticated users to execute scripts. The preview path retrieves the masseditregex-before and masseditregex-after messages in text mode, concatenates them with HTML, and passes them as raw diff headers without sanitization. Exploitation requires permission to edit system messages and a user with MassEditRegex access to preview a change, enabling script execution in that viewer's browser.

CVSS severity5.6
Medium
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Wikimedia Foundation MassEditRegex before 1.39.13, 1.42.7, and 1.43.2 allows remote authenticated users to execute scripts. The preview path retrieves the masseditregex-before and masseditregex-after messages in text mode, concatenates them with HTML, and passes them as raw diff headers without sanitization. Exploitation requires permission to edit system messages and a user with MassEditRegex access to preview a change, enabling script execution in that viewer's browser.

The record

CVE
CVE-2025-53500
Published
Jul 3, 2025
Updated
Jul 10, 2025
Vendor
Wikimedia Foundation
Product
MassEditRegex
Classifications
CWE-79, CAPEC-592, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 3, 2025CVE publishedPublication date reported by the CVE source.
  2. Jul 10, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=1.39.x <1.39.13
  2. Affected versionversion=1.42.x <1.42.7
  3. Affected versionversion=1.43.x <1.43.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Wikimedia Foundation · MassEditRegexversion=1.39.x <1.39.13; version=1.42.x <1.42.7; version=1.43.x <1.43.2

Published CVSS scores

5.6CISA ADPCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CAPEC-592Stored XSS
T1059.007JavaScript/JScript

Public exploit references

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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