Medium severity · published Apr 3, 2026
CVE-2026-35544
An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14
5.3
CVSS
0.4%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 30% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
WE
Webmail · Roundcube
before 1.5.14; 1.6.0 before 1.6.14 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-35544
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-35544
Patch
https://github.com/roundcube/roundcubemail/commit/099009b9c8e1d3c636fb9a5af72f7c2596018662
Patch
https://github.com/roundcube/roundcubemail/commit/226811a1c974271dbedca72672923abaff8191c0
Patch
https://github.com/roundcube/roundcubemail/commit/57dec0c127b98e0c8e3b9c26c80049b9c4bcaea7
Release Notes
https://github.com/roundcube/roundcubemail/releases/tag/1.5.14
Release Notes
https://github.com/roundcube/roundcubemail/releases/tag/1.6.14
Release Notes
https://github.com/roundcube/roundcubemail/releases/tag/1.7-rc5
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