Roundcube Webmail up to 1.5.13/1.6.13 HTML Mail Message resource transfer

Summaryinfo

A vulnerability was found in Roundcube Webmail up to 1.5.13/1.6.13 and classified as problematic. Affected by this vulnerability is an unknown functionality of the component HTML Mail Message Handler. Such manipulation leads to resource transfer. This vulnerability is listed as CVE-2026-35544. The attack may be performed from remote. There is no available exploit. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Roundcube Webmail up to 1.5.13/1.6.13. It has been rated as problematic. Affected by this issue is an unknown code of the component HTML Mail Message Handler. The manipulation with an unknown input leads to a resource transfer vulnerability. Using CWE to declare the problem leads to CWE-669. The product does not properly transfer a resource/behavior to another sphere, or improperly imports a resource/behavior from another sphere, in a manner that provides unintended control over that resource. Impacted is integrity. CVE summarizes:

An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. Insufficient Cascading Style Sheets (CSS) sanitization in HTML e-mail messages may lead to a fixed-position mitigation bypass via the use of !important.

The advisory is available at roundcube.net. This vulnerability is handled as CVE-2026-35544 since 04/03/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. The technical details are unknown and an exploit is not available.

Upgrading to version 1.5.14 or 1.6.14 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch 099009b9c8e1d3c636fb9a5af72f7c2596018662 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Type

• Mail Client Software

Vendor

• Roundcube

Name

• Webmail

Version

• 1.5.0
• 1.5.1
• 1.5.2
• 1.5.3
• 1.5.4
• 1.5.5
• 1.5.6
• 1.5.7
• 1.5.8
• 1.5.9
• 1.5.10
• 1.5.11
• 1.5.12
• 1.5.13
• 1.6.0
• 1.6.1
• 1.6.2
• 1.6.3
• 1.6.4
• 1.6.5
• 1.6.6
• 1.6.7
• 1.6.8
• 1.6.9
• 1.6.10
• 1.6.11
• 1.6.12
• 1.6.13

License

• free

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

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CVSSv3info

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Exploitinginfo

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Entryinfo

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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