---
title: "CVE-2023-5631: Roundcube Webmail Persistent Cross-Site Scripting (XSS) Vulnerability"
url: https://erroneo.us/security/cve/CVE-2023-5631/
description: "CVE-2023-5631 (Roundcube Webmail): Exploited in the wild (CISA KEV). Roundcube before 1.4.15, 1.5.x before 1.5.5, and 1.6.x before 1.6.4 allows stored XSS…"
type: vulnerability-record
section: "Security Digest"
date_published: 2023-10-18
date_modified: 2025-10-21
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2023-5631"
kev: true
cvss: 6.1
epss: 0.76901
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2023-5631: Roundcube Webmail Persistent 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 2023-10-26, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2023-11-16 ; treat that as the outer limit, not the target.
- EPSS 76.9% , percentile 99.6: FIRST’s model estimates a 76.9% chance of exploitation activity in the next 30 days, higher than 99.6% 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

Roundcube before 1.4.15, 1.5.x before 1.5.5, and 1.6.x before 1.6.4 allows stored XSS via an HTML e-mail message with a crafted SVG document because of program/lib/Roundcube/rcubewashtml.php behavior. This could allow a remote attacker to load arbitrary JavaScript code.

## Affected products (CVE record)

- Roundcube Roundcubemail: 1.6.0 < 1.6.3, 1.5.0 < 1.5.4, 1.4.0 < 1.5.14

## Severity

- ESET CVSS 3.1: 6.1 `CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N`

## Exploitation

- CISA KEV: added 2023-10-26; federal due date 2023-11-16. 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 total .
- FIRST EPSS (model of 2026-10-21): 76.90% probability of exploitation activity in the next 30 days; percentile 99.6.

## Sources

- [Listed in CISA KEV notes (roundcube.net)](https://roundcube.net/news/2023/10/16/security-update-1.6.4-released)
- [Listed in CISA KEV notes (roundcube.net)](https://roundcube.net/news/2023/10/16/security-updates-1.5.5-and-1.4.15)
- [CVE.org record CVE-2023-5631](https://www.cve.org/CVERecord?id=CVE-2023-5631)
- [NVD entry CVE-2023-5631](https://nvd.nist.gov/vuln/detail/CVE-2023-5631)
- [CISA Known Exploited Vulnerabilities catalog entry](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-5631)
- [github.com](https://github.com/roundcube/roundcubemail/commit/6ee6e7ae301e165e2b2cb703edf75552e5376613)
- [github.com](https://github.com/roundcube/roundcubemail/releases/tag/1.6.4)
- [github.com](https://github.com/roundcube/roundcubemail/releases/tag/1.5.5)
- [github.com](https://github.com/roundcube/roundcubemail/releases/tag/1.4.15)
- [github.com](https://github.com/roundcube/roundcubemail/issues/9168)
- [github.com](https://github.com/roundcube/roundcubemail/commit/41756cc3331b495cc0b71886984474dc529dd31d)
- [bugs.debian.org](https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1054079)
- [debian.org](https://www.debian.org/security/2023/dsa-5531)
- [lists.debian.org](https://lists.debian.org/debian-lts-announce/2023/10/msg00035.html)
- [openwall.com](http://www.openwall.com/lists/oss-security/2023/11/01/1)
- [openwall.com](http://www.openwall.com/lists/oss-security/2023/11/01/3)
- [lists.fedoraproject.org](https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/LK67Q46OIEGJCRQUBHKLH3IIJTBNGGX4/)
- [openwall.com](http://www.openwall.com/lists/oss-security/2023/11/17/2)

---
Source page: https://erroneo.us/security/cve/CVE-2023-5631/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt