What’s Vulnerable › Vulnerabilities

CVE-2026-35540

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-04-03 · updated 2026-07-24
• Weakness: CWE-669

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.

Affected products

• Roundcube Webmail: from 1.6.0 before 1.6.14 — fixed in 1.6.14

How to fix

Upgrade to a fixed version: Roundcube Webmail 1.6.14. Check the vendor advisory for mitigations.

References

• https://github.com/roundcube/roundcubemail/commit/27ec6cc9cb25e1ef8b4d4ef39ce76d619caa6870
• https://github.com/roundcube/roundcubemail/commit/579b68eff90650a5c782e153debd66c765648942
• https://github.com/roundcube/roundcubemail/releases/tag/1.6.14
• https://github.com/roundcube/roundcubemail/releases/tag/1.7-rc5
• https://roundcube.net/news/2026/03/18/security-updates-1.7-rc5-1.6.14-1.5.14

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