Roundcube Webmail up to 1.6.16/1.7.1 CSS server-side request forgery

Summaryinfo

A vulnerability was found in Roundcube Webmail up to 1.6.16/1.7.1. It has been rated as problematic. This issue affects some unknown processing of the component CSS. The manipulation leads to server-side request forgery. This vulnerability is documented as CVE-2026-62643. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Roundcube Webmail up to 1.6.16/1.7.1. This issue affects an unknown function of the component CSS. The manipulation with an unknown input leads to a server-side request forgery vulnerability. Using CWE to declare the problem leads to CWE-918. The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. Impacted is confidentiality. The summary by CVE is:

In Roundcube Webmail before 1.6.17 and 1.7.x before 1.7.2, 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. NOTE: this issue exists because of insufficient fixes for CVE-2026-35540 and CVE-2026-48843.

It is possible to read the advisory at roundcube.net. The identification of this vulnerability is CVE-2026-62643 since 07/14/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. It demands that the victim is doing some kind of user interaction. The technical details are unknown and an exploit is not publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 327051 (Linux Distros Unpatched Vulnerability : CVE-2026-62643), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 1.6.17 or 1.7.2 eliminates this vulnerability.

The vulnerability is also documented in the databases at CNNVD (CNNVD-2026-99036270), Tenable (327051) and CERT Bund (WID-SEC-2026-2207). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

• Fedora Linux
• Open Source Roundcube

Productinfo

Type

• Mail Client Software

Vendor

• Roundcube

Name

• Webmail

Version

• 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
• 1.6.14
• 1.6.15
• 1.6.16
• 1.7.0
• 1.7.1

License

• free

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

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Exploitinginfo

Threat Intelligenceinfo

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Entryinfo

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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