CVE-2024-42009 Roundcube CVE debrief

Who should care

Administrators and security teams running Roundcube Webmail, managed service providers hosting it, cloud mail platform operators, and incident responders responsible for email-facing web applications.

Technical summary

The supplied official sources identify CVE-2024-42009 as a Cross-Site Scripting vulnerability in Roundcube Webmail. The CISA KEV entry confirms known exploitation and sets a remediation due date of 2025-06-30. The source note points to Roundcube security updates 1.6.8 and 1.5.8 as the vendor-linked remediation reference. No CVSS score or deeper attack-precondition details were included in the supplied corpus.

Defensive priority

Immediate

Recommended defensive actions

• Inventory all Roundcube Webmail deployments and confirm whether they are exposed to users or reachable from the internet.
• Apply the vendor’s security-update guidance referenced by CISA, including the Roundcube 1.6.8 and 1.5.8 security update notice.
• If you cannot mitigate promptly, follow CISA guidance for cloud services and consider discontinuing use of the product until remediation is available.
• Review access, authentication, and application logs for suspicious activity involving Roundcube hosts around the KEV date.
• Coordinate with hosted-service providers or MSPs to confirm patch status, compensating controls, and remediation timelines before the CISA due date.

Evidence notes

CISA’s KEV feed lists CVE-2024-42009 as “RoundCube Webmail Cross-Site Scripting Vulnerability” for vendor/project Roundcube and product Webmail, with dateAdded 2025-06-09 and dueDate 2025-06-30. The KEV note also references the Roundcube security updates 1.6.8 and 1.5.8 page and the NVD detail page. The supplied corpus does not include a CVSS score or additional technical detail beyond the XSS classification and known-exploitation status.

Official resources