---
title: "CVE-2020-13965: Roundcube Webmail Cross-Site Scripting (XSS) Vulnerability"
url: https://erroneo.us/security/cve/CVE-2020-13965/
description: "CVE-2020-13965 (Roundcube Webmail): Exploited in the wild (CISA KEV). An issue was discovered in Roundcube Webmail before 1.3.12 and 1.4.x before 1.4.5.…"
type: vulnerability-record
section: "Security Digest"
date_published: 2020-06-09
date_modified: 2025-10-21
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2020-13965"
kev: true
cvss: 6.3
epss: 0.76596
license: All rights reserved. Quote with attribution and a link.
---

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

**Signal:** Exploited: patch now if you run it. CISA has confirmed exploitation in the wild. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Yes, if you run Roundcube Webmail. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2024-06-26, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2024-07-17 ; treat that as the outer limit, not the target.
- EPSS 76.6% , percentile 99.5: FIRST’s model estimates a 76.6% chance of exploitation activity in the next 30 days, higher than 99.5% of all scored CVEs (very high). EPSS is a probability, not a verdict.
- Needs a user to click or open something. Phishing makes that realistic, but it is not wormable.

## What it is

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 (CVE record)

- n/a n/a: see advisory

## Severity

- CISA-ADP CVSS 3.1: 6.3 `CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L`

## Exploitation

- CISA KEV: added 2024-06-26; federal due date 2024-07-17. Known ransomware use: Unknown.
- CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
- CISA SSVC assessment: exploitation active , automatable no , technical impact partial .
- FIRST EPSS (model of 2026-10-21): 76.60% probability of exploitation activity in the next 30 days; percentile 99.5.

## Sources

- [DSA-4700](https://www.debian.org/security/2020/dsa-4700)
- [FEDORA-2020-2a1a6a8432](https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DLESQ4LPJGMSWHQ4TBRTVQRDG7IXAZCW/)
- [FEDORA-2020-aeffd92b77](https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ODPJXBHZ32QSP4MYT2OBCALYXSUJ47SK/)
- [Listed in CISA KEV notes (roundcube.net)](https://roundcube.net/news/2020/06/02/security-updates-1.4.5-and-1.3.12)
- [CVE.org record CVE-2020-13965](https://www.cve.org/CVERecord?id=CVE-2020-13965)
- [NVD entry CVE-2020-13965](https://nvd.nist.gov/vuln/detail/CVE-2020-13965)
- [CISA Known Exploited Vulnerabilities catalog entry](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-13965)
- [github.com](https://github.com/roundcube/roundcubemail/releases/tag/1.4.5)
- [github.com](https://github.com/roundcube/roundcubemail/releases/tag/1.3.12)
- [github.com](https://github.com/roundcube/roundcubemail/commit/884eb611627ef2bd5a2e20e02009ebb1eceecdc3)
- [github.com](https://github.com/roundcube/roundcubemail/compare/1.4.4...1.4.5)
- [github.com](https://github.com/DrunkenShells/Disclosures/tree/master/CVE-2020-13965-Cross%20Site-Scripting%20via%20Malicious%20XML%20Attachment-Roundcube)

---
Source page: https://erroneo.us/security/cve/CVE-2020-13965/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt