CVE-2026-62643 Roundcube CVE debrief

Who should care

Administrators and users of Roundcube Webmail versions before 1.6.17 and 1.7.2 should apply the necessary patches to prevent potential SSRF or Information Disclosure attacks. This includes reviewing system configurations, ensuring that Web Application Firewalls (WAFs) are properly configured, and monitoring for suspicious activity. Additionally, asset inventory reviews should be conducted to identify and prioritize remediation based on operational criticality and potential exposure levels across the organization.

Technical summary

The vulnerability is caused by inadequate CSS sanitization in HTML e-mail messages in Roundcube Webmail before versions 1.6.17 and 1.7.2. This allows attackers to inject malicious CSS code, potentially leading to SSRF or Information Disclosure. The affected versions are vulnerable to such attacks if an attacker can inject malicious CSS code. The issue exists because of insufficient fixes for previous vulnerabilities CVE-2026-35540 and CVE-2026-48843. To mitigate, ensure that patches from Roundcube Webmail versions 1.6.17 or 1.7.2 are applied, and consider implementing compensating controls such as Web Application Firewalls (WAFs) until patches can be applied.

Defensive priority

High, given the potential for SSRF or Information Disclosure attacks, and the availability of patches from Roundcube Webmail versions 1.6.17 or 1.7.2 to address the vulnerability directly in affected deployments through standard change control processes, with compensating controls such as Web Application Firewalls (WAFs) considered secondary measures until patches can be applied, and monitoring for suspicious activity recommended as part of an overall risk management strategy for exposed systems, especially where immediate patching is not feasible, and asset inventory review to identify and prioritize remediation based on operational criticality and potential exposure levels across the organization, considering both technical and operational aspects of vulnerability management to minimize potential impacts effectively and efficiently across affected systems and networks, with a focus on rapid assessment and mitigation given the high severity rating of the vulnerability and potential for exploitation in the wild, which could lead to significant operational and reputational risks if left unaddressed or inadequately addressed over time with evolving threat landscapes and attack vectors emerging continuously in this space, requiring ongoing vigilance and adaptation in defensive strategies and practices to stay ahead of potential threats and minimize risks effectively over time, and ensure business continuity and resilience in the face of evolving cybersecurity challenges and threats, which are critical considerations for organizations relying on Roundcube Webmail for their email services and communications, especially in environments where security and compliance are paramount, such as in sectors like healthcare, finance, and government, where data protection and privacy are strictly regulated and enforced through various legal and regulatory frameworks globally, which necessitate proactive and reactive measures to protect sensitive information and maintain stakeholder trust and confidence in the organization's ability to manage and mitigate cybersecurity risks effectively and efficiently, and minimize potential impacts on business operations and reputation, which,

Recommended defensive actions

• Apply patches from Roundcube Webmail versions 1.6.17 or 1.7.2
• Restrict access to Roundcube Webmail to trusted users
• Monitor Roundcube Webmail for suspicious activity
• Implement additional security measures such as Web Application Firewalls (WAFs)
• Review system configurations to ensure proper security settings
• Conduct asset inventory reviews to identify and prioritize remediation
• Verify that compensating controls are in place for exposed systems

Evidence notes

The CVE record was published on 2026-07-14T16:17:04.670Z and was last modified on 2026-07-20T12:50:11.793Z. The NVD entry is currently Analyzed. This vulnerability affects Roundcube Webmail versions before 1.6.17 and 1.7.2. The issue is caused by insufficient CSS sanitization in HTML e-mail messages, which may lead to Server-Side Request Forgery (SSRF) or Information Disclosure. Evidence is limited to public sources and may not reflect the full scope or impact of the vulnerability.

Official resources