CVE-2026-35540 Details
Description
An issue was discovered in Roundcube Webmail 1.6.0 before 1.6.14. Insufficient Cascading Style Sheets (CSS) sanitization in HTML e-mail messages may lead to SSRF or Information Disclosure, e.g., if stylesheet links point to local network hosts.
A vulnerability exists in Roundcube Webmail versions 1.6.0 prior to 1.6.14, and in the 1.7 release candidates, specifically 1.7-rc5 and 1.7-rc6. The issue arises from inadequate sanitization of Cascading Style Sheets (CSS) in HTML email messages. This flaw may allow Server-Side Request Forgery (SSRF) or unauthorized information disclosure, particularly if the stylesheet links reference local network hosts.
Users can update to Roundcube Webmail versions 1.6.14 or 1.7-rc6, both of which include the necessary fix. Instructions for updating are available in the release notes on the Roundcube GitHub repository.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Apr 3, 2026References to Advisories, Solutions, and Tools
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-669 | Incorrect Resource Transfer Between Spheres | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| roundcube webmail | >= 1.6.0, < 1.6.14 |
CPE
Remediation
| |
Change History
5 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 24, 2026 | CVE Translated | [email protected] |
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Apr 7, 2026 | Initial Analysis | [email protected] |
| Apr 3, 2026 | New CVE Received | [email protected] |