CVE-2020-13965: Roundcube Webmail Cross-Site Scripting (XSS) Vulnerability

Severity: medium (CVSS 6.1 v3.1)
Exploited in the wild: yes — in CISA KEV since 2024-06-26
EPSS: 76.6% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2020-06-09 · updated 2026-06-17
Weakness: CWE-79

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.

Affected products

Debian Linux: 9.0, 10.0
Fedoraproject Fedora: 31, 32
Roundcube Webmail: before 1.3.12; from 1.4.0 before 1.4.5 — fixed in 1.3.12, 1.4.5

How to fix

Upgrade to a fixed version: Roundcube Webmail 1.3.12, 1.4.5. Check the vendor advisory for mitigations.

References

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

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