CVE-2026-62642 Roundcube CVE debrief

Who should care

Users of Roundcube Webmail before 1.6.17 and 1.7.x before 1.7.2 should be aware of this vulnerability and take steps to mitigate it. This includes administrators of Roundcube Webmail instances, security teams responsible for vulnerability management, and operators who may be impacted by potential denial-of-service attacks. Reviewing and implementing vendor guidance is crucial to prevent potential service disruptions.

Technical summary

The vulnerability is caused by an infinite loop in the TNEF decoder in Roundcube Webmail before 1.6.17 and 1.7.x before 1.7.2. This may lead to denial of service upon opening an email with a TNEF attachment. The vulnerability has a CVSS score of 4.3 and a CVSS severity of MEDIUM. Affected systems may experience service disruption or crashes when processing malicious TNEF attachments. Technical details are limited to CVE and NVD entries.

Defensive priority

Medium

Recommended defensive actions

• Inventory and check for affected Roundcube Webmail versions
• Apply patches or updates to vulnerable systems
• Monitor for suspicious email activity
• Implement compensating controls to prevent exploitation
• Review and test vendor-provided patches
• Verify vulnerability presence in environment
• Track exceptions and retest remediated assets

Evidence notes

The CVE record and NVD entry provide evidence of the vulnerability and its impact. The vendor has released patches and updates to mitigate the vulnerability. However, the scope of affected systems and potential impact on organizations is not fully clear. Defenders should verify the vulnerability's presence in their environment, review vendor guidance, and implement compensating controls if necessary. Evidence is limited to CVE and NVD entries, which may not cover all potential deployment scenarios.

Official resources