CVE-2026-114722

roundcubemail: Roundcube Webmail: Interface spoofing via CSS scoping bypass in HTML messages

Published Oct 22, 2026 CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed
Description
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”.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DSA Debian DSA DSA-6579-1 roundcube security update
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Title CSS Scoping Bypass in Roundcube Webmail Enables UI Redressing roundcubemail: Roundcube Webmail: Interface spoofing via CSS scoping bypass in HTML messages
Weaknesses CWE-1021
References
Metrics threat_severity

None

threat_severity

Moderate

Type Values Removed Values Added
Title CSS Scoping Bypass in Roundcube Webmail Enables UI Redressing
Type Values Removed Values Added
Description 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”.
First Time appeared Roundcube
Roundcube webmail
Weaknesses CWE-669
CPEs cpe:2.3:a:roundcube:webmail:*:*:*:*:*:*:*:*
Vendors & Products Roundcube
Roundcube webmail
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
mitre
Published
Updated
Oct 28, 2026, 2:13 AM
Reserved
Oct 22, 2026, 1:39 AM
Status
Analyzed
Published
Oct 22, 2026, 2:17 AM
Modified
Nov 2, 2026, 6:42 PM
Severity
Moderate
Public date
Oct 22, 2026, 1:39 AM