CVE-2026-74997: Roundcube Webmail

High severity, CVSS 8.8. EPSS: 1.1% chance of exploitation in the next 30 days.

In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, the cmd_learn driver of the markasjunk plugin is subject to remote code execution via crafted placeholder replacement values. This issue only affects Roundcube instances using the markasjunk plugin with its cmd_learn driver.

Affected products

• Roundcube Webmail: from 1.6.0, before 1.6.18 (fixed in 1.6.18); from 1.7.0, before 1.7.3 (fixed in 1.7.3)

Published 2026-08-17. Last modified 2026-09-08.