RoundCube Webmail Cross-Site Scripting Vulnerability

Added to KEV
2025-06-09
Federal due date
2025-06-30
Vendor
Roundcube
Product
Webmail
EPSS
99.7th percentile (score 0.912, as of 2026-06-08)
NVD CVSS v3.1
Ransomware use
Unknown
Upstream
https://nvd.nist.gov/vuln/detail/CVE-2024-42009

CISA short description

RoundCube Webmail contains a cross-site scripting vulnerability. This vulnerability could allow 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.

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.

EPSS percentile is the FIRST.org exploit-probability ranking as of the date noted above; it moves daily. CVSS reflects NVD's analysis at time of publication.