Home/CVE/An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. Insufficient Cascading Style Sheets (CSS) sanitiz
CVE

CVE-2026-35544

An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. Insufficient Cascading Style Sheets (CSS) sanitiz

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.

MEDIUM · CVSS 5.3 EPSS 0.00015
Schedule remediation
  • SSVC automatable: yes - attacks can be scripted at scale
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-669Incorrect Resource Transfer Between Spheres
▤

Affected Products & Versions

2
roundcube webmail<= 1.5.13
roundcube webmail>= 1.6.0 and <= 1.6.13
▤

Affected Packages

1
Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
Packagist roundcube/roundcubemail MEDIUM fixed in 1.7-rc5
▣

Scoring & Timeline

5.3
MEDIUM · CVSS v3.1 · cve@mitre.org
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD03 Apr 2026 · 05:16 AM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
yes
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
🔗

References & Sources

7
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://github.com/roundcube/roundcubemail/commit/099009b9c8e1d3c636fb9a5af72f7c2596018662Patch
https://github.com/roundcube/roundcubemail/commit/226811a1c974271dbedca72672923abaff8191c0Patch
https://github.com/roundcube/roundcubemail/commit/57dec0c127b98e0c8e3b9c26c80049b9c4bcaea7Patch
https://github.com/roundcube/roundcubemail/releases/tag/1.5.14Release Notes
https://github.com/roundcube/roundcubemail/releases/tag/1.6.14Release Notes
https://github.com/roundcube/roundcubemail/releases/tag/1.7-rc5Release Notes
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