Roundcube Webmail up to 1.6.15/1.7.0 Mail Message server-side request forgery

Summaryinfo

A vulnerability, which was classified as critical, has been found in Roundcube Webmail up to 1.6.15/1.7.0. This vulnerability affects unknown code of the component Mail Message Handler. The manipulation leads to server-side request forgery. This vulnerability is referenced as CVE-2026-48843. Remote exploitation of the attack is possible. No exploit is available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Roundcube Webmail up to 1.6.15/1.7.0. This issue affects an unknown functionality of the component Mail Message Handler. 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, integrity, and availability. The summary by CVE is:

Roundcube Webmail 1.6.x between 1.6.14 and 1.6.16,and 1.7.x before 1.7.1 has 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. The issue stems from an insufficient fix for CVE-2026-35540.

It is possible to read the advisory at roundcube.net. The identification of this vulnerability is CVE-2026-48843 since 05/25/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. The technical details are unknown and an exploit is not publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 316869 (Linux Distros Unpatched Vulnerability : CVE-2026-48843), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 1.6.16 or 1.7.1 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (316869) and EUVD (EUVD-2026-31718). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

• Mail Client Software

Vendor

• Roundcube

Name

• Webmail

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 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
• 1.7.0

License

• free

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

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

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