Roundcube Webmail up to 1.5.13/1.6.13 BODY Element resource transfer

Summaryinfo

A vulnerability, which was classified as problematic, was found in Roundcube Webmail up to 1.5.13/1.6.13. This impacts an unknown function of the component BODY Element Handler. The manipulation results in resource transfer. This vulnerability is identified as CVE-2026-35542. The attack can be executed remotely. There is not any exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in Roundcube Webmail up to 1.5.13/1.6.13. It has been classified as problematic. Affected is some unknown functionality of the component BODY Element Handler. The manipulation with an unknown input leads to a resource transfer vulnerability. CWE is classifying the issue as 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. This is going to have an impact on confidentiality. CVE summarizes:

An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. The remote image blocking feature can be bypassed via a crafted background attribute of a BODY element in an e-mail message. This may lead to information disclosure or access-control bypass.

The advisory is shared for download at roundcube.net. This vulnerability is traded as CVE-2026-35542 since 04/03/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are neither technical details nor an exploit publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 304882 (Linux Distros Unpatched Vulnerability : CVE-2026-35542), which helps to determine the existence of the flaw in a target environment.

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 e052328e3dc75f13adc2e314eaa4096ac21084ad 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.

The vulnerability is also documented in the databases at Tenable (304882) and CERT Bund (WID-SEC-2026-0789). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Affected

• Open Source Roundcube

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

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CPE 2.2info

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VulDB is the best source for vulnerability data and more expert information about this specific topic.

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