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MEDIUM · CVSS 6.1 CISA Known Exploited Vulnerability

CVE-2023-5631

Roundcube Webmail Persistent Cross-Site Scripting (XSS) Vulnerability

Roundcube Webmail

Roundcube before 1.4.15, 1.5.x before 1.5.5, and 1.6.x before 1.6.4 allows stored XSS via an HTML e-mail message with a crafted SVG document because of program/lib/Roundcube/rcube_washtml.php behavior. This could allow a remote attacker to load arbitrary JavaScript code.

CVSS
6.1
MEDIUM
EPSS
76.3%
30-day exploitation
Ransomware groups
0
recorded exploiting
Published
18 Oct 2023
CWE-79

Exploitation status

CISA Known Exploited Vulnerabilities

Listed by CISA on 26 October 2023. US federal agencies were required to remediate it by 16 November 2023.

EPSS — exploitation probability

FIRST puts the probability of exploitation activity in the next 30 days at 76.3%, which is higher than 99.5% 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:L/I:L/A:N

Frequently asked questions

Is CVE-2023-5631 being exploited by ransomware groups?

No ransomware group in this database is currently recorded as exploiting CVE-2023-5631.

What does CVE-2023-5631 affect?

CVE-2023-5631 affects Roundcube Webmail. Roundcube before 1.4.15, 1.5.x before 1.5.5, and 1.6.x before 1.6.4 allows stored XSS via an HTML e-mail message with a crafted SVG document because of program/lib/Roundcube/rcube_washtml.php behavior. This could allow a remote attacker to load arbitrary JavaScript code.

How severe is CVE-2023-5631?

CVE-2023-5631 is rated MEDIUM with a CVSS base score of 6.1. EPSS puts the probability of exploitation in the next 30 days at 76.3%, higher than 99.5% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 16 November 2023.

How should organisations respond to CVE-2023-5631?

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.