---
title: "CVE-2024-42009: RoundCube Webmail Cross-Site Scripting Vulnerability"
url: https://erroneo.us/security/cve/CVE-2024-42009/
description: "CVE-2024-42009 (Roundcube Webmail): Exploited in the wild (CISA KEV). A Cross-Site Scripting vulnerability in Roundcube through 1.5.7 and 1.6.x through…"
type: vulnerability-record
section: "Security Digest"
date_published: 2024-08-05
date_modified: 2025-10-21
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2024-42009"
kev: true
cvss: 9.3
epss: 0.82882
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2024-42009: RoundCube Webmail Cross-Site Scripting 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 2025-06-09, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2025-06-30 ; treat that as the outer limit, not the target.
- EPSS 82.9% , percentile 99.7: FIRST’s model estimates a 82.9% chance of exploitation activity in the next 30 days, higher than 99.7% 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

A Cross-Site Scripting vulnerability in Roundcube through 1.5.7 and 1.6.x through 1.6.7 allows a remote attacker to steal and send emails of a victim via a crafted e-mail message that abuses a Desanitization issue in messagebody() in program/actions/mail/show.php.

## Affected products (CVE record)

- n/a n/a: see advisory

## Severity

- CISA-ADP CVSS 3.1: 9.3 `CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N`

## Exploitation

- CISA KEV: added 2025-06-09; federal due date 2025-06-30. Known ransomware use: Unknown.
- CISA required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, 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): 82.88% probability of exploitation activity in the next 30 days; percentile 99.7.

## Sources

- [Listed in CISA KEV notes (roundcube.net)](https://roundcube.net/news/2024/08/04/security-updates-1.6.8-and-1.5.8)
- [CVE.org record CVE-2024-42009](https://www.cve.org/CVERecord?id=CVE-2024-42009)
- [NVD entry CVE-2024-42009](https://nvd.nist.gov/vuln/detail/CVE-2024-42009)
- [CISA Known Exploited Vulnerabilities catalog entry](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-42009)
- [github.com](https://github.com/roundcube/roundcubemail/releases)
- [sonarsource.com](https://sonarsource.com/blog/government-emails-at-risk-critical-cross-site-scripting-vulnerability-in-roundcube-webmail/)
- [github.com](https://github.com/roundcube/roundcubemail/releases/tag/1.5.8)
- [github.com](https://github.com/roundcube/roundcubemail/releases/tag/1.6.8)

---
Source page: https://erroneo.us/security/cve/CVE-2024-42009/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt