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CRITICAL · CVSS 9.3 CISA Known Exploited Vulnerability

CVE-2024-42009

RoundCube Webmail Cross-Site Scripting Vulnerability

Roundcube Webmail

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 message_body() in program/actions/mail/show.php.

CVSS
9.3
CRITICAL
EPSS
82.9%
30-day exploitation
Ransomware groups
0
recorded exploiting
Published
5 Aug 2024
CWE-79

Exploitation status

CISA Known Exploited Vulnerabilities

Listed by CISA on 9 June 2025. US federal agencies were required to remediate it by 30 June 2025.

EPSS — exploitation probability

FIRST puts the probability of exploitation activity in the next 30 days at 82.9%, which is higher than 99.7% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N

Frequently asked questions

Is CVE-2024-42009 being exploited by ransomware groups?

No ransomware group in this database is currently recorded as exploiting CVE-2024-42009.

What does CVE-2024-42009 affect?

CVE-2024-42009 affects Roundcube Webmail. 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 message_body() in program/actions/mail/show.php.

How severe is CVE-2024-42009?

CVE-2024-42009 is rated CRITICAL with a CVSS base score of 9.3. EPSS puts the probability of exploitation in the next 30 days at 82.9%, higher than 99.7% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 30 June 2025.

How should organisations respond to CVE-2024-42009?

Apply the vendor patch for Roundcube Webmail as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.