CVE-2026-75000 Roundcube CVE debrief

Who should care

System administrators and security teams responsible for Roundcube Webmail installations should be aware of this vulnerability and take appropriate actions to mitigate potential risks. They should review the official CVE record and NVD entry for detailed information, verify affected versions, apply patches or updates, and monitor for potential exploitation attempts. Additionally, they should ensure that compensating controls are in place for exposed systems and review relevant monitoring, detection, and logs for exposed assets.

Technical summary

CVE-2026-75000 is a medium-severity vulnerability in Roundcube Webmail, affecting versions before 1.6.18 and 1.7.x before 1.7.3. The issue involves improper HTML/CSS sanitization of the SVG animate 'by' attribute, which may allow remote image blocking bypass. This bypass could potentially lead to information disclosure or privilege escalation. The vulnerability was publicly disclosed, and affected vendors have released patches to address the issue.

Defensive priority

Medium priority due to potential information disclosure or privilege escalation.

Recommended defensive actions

• Inventory and verify Roundcube Webmail versions
• Apply vendor patches or updates
• Monitor for potential exploitation attempts
• Review compensating controls for exposed systems
• Check relevant monitoring, detection, and logs for exposed assets
• Track exceptions and retest remediated assets
• Confirm whether affected product deployments exist in managed environments

Evidence notes

The CVE-2026-75000 record indicates improper HTML/CSS sanitization of the SVG animate 'by' attribute in Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, which may lead to remote image blocking bypass, potentially resulting in information disclosure or privilege escalation. However, detailed information about affected configurations and exploitation is limited.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.