CVE-2026-35538 Roundcube CVE debrief

Who should care

Organizations using Roundcube Webmail versions prior to 1.5.14 or 1.6.14 should apply the necessary patches to prevent potential IMAP injection or CSRF bypass attacks. Security teams and vulnerability management teams should review the CVE record and NVD entry to understand the impact and available patches.

Technical summary

The vulnerability, CVE-2026-35538, exists in Roundcube Webmail before versions 1.5.14 and 1.6.14. It is caused by unsanitized IMAP SEARCH command arguments, which could lead to IMAP injection or CSRF bypass during mail search. The CVSS score for this vulnerability is 3.1, indicating a low severity. Organizations should apply patches to update Roundcube Webmail to version 1.5.14 or 1.6.14 and monitor IMAP SEARCH command usage.

Defensive priority

Apply patches to update Roundcube Webmail to version 1.5.14 or 1.6.14. Monitor and restrict IMAP SEARCH command usage. Conduct regular security audits and vulnerability assessments.

Recommended defensive actions

• Apply patches to update Roundcube Webmail to version 1.5.14 or 1.6.14
• Monitor and restrict IMAP SEARCH command usage
• Conduct regular security audits and vulnerability assessments
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and NVD entry provide information on the vulnerability, its impact, and available patches. Roundcube has released versions 1.5.14 and 1.6.14 to address this issue. Organizations should verify their deployments and apply patches or mitigations as necessary. Evidence is limited to public sources and may not reflect the full scope or impact of the vulnerability. Defenders should review official advisories and monitor for potential IMAP injection or CSRF bypass attacks.

Official resources