Skip to content
Fencer Vulns
medium 5.3

CVE-2026-35544 json

Roundcube Webmail: Insufficient CSS sanitization in HTML e-mail messages

published 2026-04-03 7 mo ago modified 2026-07-24 3 mo ago also GHSA-xpqh-grpw-4xmg , EUVD-2026-18591

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 32%
public exploits
0
none known

Summary

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.

Patch / fix

  • packagist roundcube/roundcubemail 1.7-rc5
  • Roundcube Webmail 1.5.14, 1.6.14
  • roundcube Debian 12 1.6.5+dfsg-1+deb12u8
  • roundcube Debian 13 1.6.15+dfsg-0+deb13u1
  • roundcube Debian 14 1.6.14+dfsg-1

debian advisories DEBIAN-CVE-2026-35544

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-35544 updated cvss 5.4

roundcubemail: Roundcube Webmail: Security mitigation bypass via insufficient CSS sanitization

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
7 mo ago

Exploit prediction

0.38% chance of exploitation in the next 30 days, higher than 32% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
GitHub 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Affected packages

ecosystem package affected fixed in
packagist roundcube/roundcubemail
>=1.7-beta, <1.7-rc5
1.7-rc5

Affected products

  • Roundcube Webmail

Classification

Weakness
  • CWE-669 Incorrect Resource Transfer Between Spheres

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.