Roundcube Webmail up to 1.6.19/1.7.4 HTML message mod_css_styles HTML injection

Summaryinfo

A vulnerability was found in Roundcube Webmail up to 1.6.19/1.7.4. It has been rated as problematic. This vulnerability affects the function rcube_utils::mod_css_styles of the component HTML message Handler. This manipulation causes HTML injection. This vulnerability is handled as CVE-2026-114722. The attack can be initiated remotely. There is not any exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Roundcube Webmail up to 1.6.19/1.7.4. It has been declared as problematic. Affected by this vulnerability is the function rcube_utils::mod_css_styles of the component HTML message Handler. The manipulation with an unknown input leads to a html injection vulnerability. The CWE definition for the vulnerability is CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. As an impact it is known to affect integrity. The summary by CVE is:

Roundcube Webmail before 1.6.20 and 1.7.x before 1.7.5 is affected by a CSS scoping bypass in HTML messages. rcube_utils::mod_css_styles() did not treat an at-rule prologue such as @layer a; as a selector boundary, and did not handle selectors beginning with ::, so selectors following an at-rule were left unscoped and applied to the whole Roundcube interface instead of being confined to the message body. This allows an HTML message to restyle application chrome for UI redressing and spoofing. Upstream fixed this in the commit “Fix CSS scoping bypass in HTML messages using at-rules”.

It is possible to read the advisory at bugs.debian.org. This vulnerability is known as CVE-2026-114722 since 10/22/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1059.007 according to MITRE ATT&CK.

Upgrading to version 1.6.20 or 1.7.5 eliminates this vulnerability.

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

Productinfo

Type

• Mail Client Software

Vendor

• Roundcube

Name

• Webmail

Version

• 1.6.0
• 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
• 1.6.17
• 1.6.18
• 1.6.19
• 1.7.0
• 1.7.1
• 1.7.2
• 1.7.3
• 1.7.4

License

• free

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

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

Discussion