CVE-2026-49102
Deferred Deferred - Pending Action
Cross-Site Scripting in Webmin Mailbox Attachment

Publication date: 2026-05-27

Last updated on: 2026-05-27

Assigner: MITRE

Description
Webmin before 2.640 allows mailboxes/detach.cgi XSS via an SVG document attachment that is viewed in the mailboxes component, because image/svg+xml is used instead of a safe type (e.g., text/plain).
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Meta Information
Published
2026-05-27
Last Modified
2026-05-27
Generated
2026-06-16
AI Q&A
2026-05-27
EPSS Evaluated
2026-06-15
NVD
EUVD
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
webmin webmin to 2.640 (exc)
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Exploitability
CWE
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KEV
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CWE ID Description
CWE-79 The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
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Executive Summary

This vulnerability exists in Webmin versions before 2.640 and involves a cross-site scripting (XSS) issue in the mailboxes/detach.cgi component. The problem arises because an SVG document attachment is handled using the MIME type image/svg+xml instead of a safer type like text/plain. This allows malicious SVG content to be executed when viewed in the mailboxes component.

Impact Analysis

The vulnerability can lead to cross-site scripting attacks, which may allow an attacker to execute malicious scripts in the context of the affected Webmin application. This can result in partial compromise of confidentiality and integrity, such as stealing sensitive information or manipulating data viewed by the user. The CVSS score indicates it requires no privileges but user interaction and can impact confidentiality and integrity.

Compliance Impact

The vulnerability in Webmin before version 2.640 allows cross-site scripting (XSS) via SVG document attachments in the mailboxes component. This can lead to unauthorized script execution when viewing malicious attachments.

Such a vulnerability can impact compliance with common standards and regulations like GDPR and HIPAA because it may lead to unauthorized access or disclosure of sensitive personal or health information through exploitation of the XSS flaw.

Specifically, the risk of data leakage or manipulation due to XSS attacks could violate data protection requirements that mandate safeguarding personal data against unauthorized access or breaches.

Mitigation Strategies

To mitigate this vulnerability, you should update Webmin to version 2.640 or later where the issue is fixed.

The fix includes stricter validation and sanitization of mailbox attachments, especially SVG files, to prevent script execution by forcing them to be served as plain text.

Ensure that the filenames of attachments are properly sanitized to remove dangerous characters and prevent path traversal or script execution attacks.

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