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CVE-2024-42009: RoundCube Webmail Cross-Site Scripting Vulnerability

CVE-2024-42009 is rated critical with a CVSS v3.1 base score of 9.3 and affects Roundcube Webmail. Per its scoring, it can be exploited over the network, without authentication. CISA added it to its Known Exploited Vulnerabilities catalog on 2025-06-09, which means exploitation in the wild has been observed.

Vulnerability description

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.

Severity breakdown

CVSS v3.1 9.3: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N

Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
Attack complexity: Low. No special conditions; the attack can be repeated reliably.
Privileges required: None. No account or prior access is needed.
User interaction: Required. A user must take an action, such as opening a file or following a link.
Scope: Changed. Impact reaches beyond the vulnerable component to other resources.
Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
Availability impact: None. No effect on availability.

Underlying weakness

CWE-79: Improper Neutralization of Input During Web Page Generation

The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

Affected products

Roundcube Webmail: before 1.5.8; from 1.6.0 before 1.6.8