# CVE-2026-49102: Webmin XSS in mailboxes component via SVG attachment

Source: https://junglewise.ai/threats/cve-2026-49102-webmin-xss-in-mailboxes-component-via-svg-attachment  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-27. Updated: 2026-05-27  
License: CC BY 4.0 with a link back

CVE-2026-49102 · Severity: medium · CVSS 6.1 · Published 2026-05-27

Webmin is a web-based interface for system administration on Unix-like systems. A security vulnerability in its email management component allows an attacker to send a specially crafted email attachment that, when viewed by a user, executes malicious scripts in their browser. This could lead to unauthorized actions being performed on behalf of the user or the theft of sensitive session information.

Technologies: [Webmin](https://junglewise.ai/threats/technologies/webmin). Vendors: [Webmin](https://junglewise.ai/threats/vendors/webmin).

## Quick answers

**Is CVE-2026-49102 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-49102 being exploited in the wild.

**How severe is CVE-2026-49102?** Medium severity, with a CVSS score of 6.1, published 27 May 2026.

**Which products and versions are affected?** Webmin before 2.640.

**Is there a fix for CVE-2026-49102?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-49102 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-49102?** Check whether you run Webmin at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A Cross-Site Scripting (XSS) vulnerability exists in Webmin's mailboxes component, specifically within 'mailboxes/detach.cgi'. The issue stems from the application serving SVG document attachments using the 'image/svg+xml' MIME type instead of a safer alternative like 'text/plain'. Because SVG files can contain embedded JavaScript, an attacker can send an email with a malicious SVG attachment; when a victim views or detaches this file through the Webmin interface, the script executes within the context of the victim's session. This is a reflected XSS attack requiring user interaction. The vulnerability is addressed in version 2.640 by improving attachment handling.

## Affected products

- Webmin Webmin before 2.640

## Timeline

- 2026-05-27: disclosed
- 2026-05-27: advisory

## References

- [https://github.com/webmin/webmin/commit/cf432879a14568c4bb44cd2f9e5a9bd0e168edc1](https://github.com/webmin/webmin/commit/cf432879a14568c4bb44cd2f9e5a9bd0e168edc1)
- [https://github.com/webmin/webmin/compare/2.630...2.640](https://github.com/webmin/webmin/compare/2.630...2.640)

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