Description
An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. Insufficient Cascading Style Sheets (CSS) sanitization in HTML e-mail messages may lead to a fixed-position mitigation bypass via the use of !important.
Published: 2026-04-03
Score: 5.3 Medium
EPSS: < 1% Very Low
KEV: No
Impact: CSS injection bypasses fixed-position safeguards, potentially exposing hidden UI elements.
Action: Immediate Patch
AI Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Remediation

No vendor fix or workaround currently provided.

Additional remediation guidance may be available on OpenCVE Cloud.

Tracking

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Advisories
Source ID Title
Debian DSA Debian DSA DSA-6196-1 roundcube security update
Github GHSA Github GHSA GHSA-xpqh-grpw-4xmg Roundcube Webmail: Insufficient CSS sanitization in HTML e-mail messages
History

Thu, 09 Apr 2026 08:30:00 +0000

Type Values Removed Values Added
Title Fixed-Position Mitigation Bypass via CSS Injection in Roundcube Webmail

Thu, 09 Apr 2026 01:15:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:a:roundcube:webmail:*:*:*:*:*:*:*:*

Fri, 03 Apr 2026 14:00:00 +0000

Type Values Removed Values Added
Metrics ssvc

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


Fri, 03 Apr 2026 10:15:00 +0000

Type Values Removed Values Added
Title Fixed-Position Mitigation Bypass via CSS Injection in Roundcube Webmail
First Time appeared Roundcube
Roundcube webmail
Vendors & Products Roundcube
Roundcube webmail

Fri, 03 Apr 2026 05:15:00 +0000

Type Values Removed Values Added
Description An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. Insufficient Cascading Style Sheets (CSS) sanitization in HTML e-mail messages may lead to a fixed-position mitigation bypass via the use of !important.
Weaknesses CWE-669
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N'}


Subscriptions

Roundcube Webmail
cve-icon MITRE

Status: PUBLISHED

Assigner: mitre

Published:

Updated: 2026-04-03T12:50:12.338Z

Reserved: 2026-04-03T03:59:48.463Z

Link: CVE-2026-35544

cve-icon Vulnrichment

Updated: 2026-04-03T12:50:09.218Z

cve-icon NVD

Status : Analyzed

Published: 2026-04-03T05:16:22.810

Modified: 2026-04-09T01:09:00.530

Link: CVE-2026-35544

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-04-09T08:29:18Z

Weaknesses