Roundcube Webmail Cross-Site Scripting (XSS) Vulnerability

Added to KEV
2023-06-22
Federal due date
2023-07-13
Vendor
Roundcube
Product
Roundcube Webmail
EPSS
98.6th percentile (score 0.674, as of 2026-06-08)
NVD CVSS v3.1
Ransomware use
Unknown
Upstream
https://nvd.nist.gov/vuln/detail/CVE-2020-35730

CISA short description

Roundcube Webmail contains a cross-site scripting (XSS) vulnerability that allows an attacker to send a plain text e-mail message with Javascript in a link reference element that is mishandled by linkref_addinindex in rcube_string_replacer.php.

Required action

Apply updates per vendor instructions.

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.