Roundcube Webmail up to 1.5.12/1.6.12 SVG unprotected alternate channel

Summaryinfo

A vulnerability, which was classified as problematic, has been found in Roundcube Webmail up to 1.5.12/1.6.12. This issue affects some unknown processing of the component SVG Handler. The manipulation leads to unprotected alternate channel. This vulnerability is referenced as CVE-2026-25916. Remote exploitation of the attack is possible. No exploit is available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Roundcube Webmail up to 1.5.12/1.6.12 and classified as problematic. This issue affects an unknown functionality of the component SVG Handler. The manipulation with an unknown input leads to a unprotected alternate channel vulnerability. Using CWE to declare the problem leads to CWE-420. The product protects a primary channel, but it does not use the same level of protection for an alternate channel. Impacted is confidentiality. The summary by CVE is:

Roundcube Webmail before 1.5.13 and 1.6 before 1.6.13, when "Block remote images" is used, does not block SVG feImage.

It is possible to read the advisory at nullcathedral.com. The identification of this vulnerability is CVE-2026-25916 since 02/09/2026. 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 298453 (Linux Distros Unpatched Vulnerability : CVE-2026-25916), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 1.5.13 or 1.6.13 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (298453) and CERT Bund (WID-SEC-2026-0357). Be aware that VulDB is the high quality source for vulnerability data.

Affected

• Debian Linux
• Ubuntu Linux
• SUSE openSUSE
• 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
• 1.6.0
• 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

License

• free

CPE 2.3info

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CPE 2.2info

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Entryinfo

Be aware that VulDB is the high quality source for vulnerability data.

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