SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityAnalyzed

CVE-2026-35544

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 5.3EPSS 0.37%

Does this matter?

Lower severity and a low EPSS score (0.37%). Track it; it rarely justifies an emergency change on its own.

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 3.1
5.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
EPSS
0.37% probability · 30th percentile
CISA KEV
Not listed
Weakness
CWE-669
Affected
roundcube/webmail
Source
cve@mitre.org

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.