RCE in Roundcube Webmail
CVE-2026-75004
In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, improper rule name quoting could lead to managesieve_disabled_actions setting bypass via a crafted rule name in a Sieve script. This issue only affects Roundcube instances using the managesieve plugin.
Vulnerability class: Command Injection (OS Command Injection)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N.
EPSS exploit prediction
EPSS: 0.004 (28.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 29th percentile — 28.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.001
Affected products
- Roundcube Webmail — versions 1.6.0, 1.7.0
Weakness classification (CWE)
References
- github.com/roundcube/roundcubemail/releases/tag/1.6.18 (Release Notes)
- github.com/roundcube/roundcubemail/releases/tag/1.7.3 (Release Notes)
- roundcube.net/news/2026/08/09/security-updates-1.6.18-and-1.7.3 (Vendor Advisory)
Frequently asked questions
- What is CVE-2026-75004?
- CVE-2026-75004 is a medium-severity vulnerability in Roundcube Webmail, classified under Command Injection. CVSS score: 4.3/10. Published 2026-08-17.
- How severe is CVE-2026-75004?
- Medium severity. CVSS v3 base score is 4.3 out of 10.