CVE-2026-74998

EUVD-2026-60165
In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, responses from the CSS (Cascading Style Sheets) proxy were not validated, which may result in information disclosure or XSS (cross-site scripting) via MIME sniffing.
Cross-site Scripting
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
mitreCNA
7.2 HIGH
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
roundcubewebmail
1.6.0 ≤
𝑥
< 1.6.18
CNA
roundcubewebmail
1.7.0 ≤
𝑥
< 1.7.3
CNA
Debian logo
Debian Releases
Debian Product
Codename
roundcube
bookworm
vulnerable
bookworm (security)
vulnerable
bullseye
vulnerable
bullseye (security)
vulnerable
forky
1.6.18+dfsg-1
fixed
sid
1.6.18+dfsg-1
fixed
trixie
vulnerable
trixie (security)
vulnerable
Common Weakness Enumeration
References
https://github.com/roundcube/roundcubemail/commit/62d33c8a0dc3fd0dd03984220dc9709e8e0de43b
https://github.com/roundcube/roundcubemail/commit/a2334990c02f7cb77b1a8d6fa97fcd9e1b5cd1fb
https://github.com/roundcube/roundcubemail/releases/tag/1.6.18
https://github.com/roundcube/roundcubemail/releases/tag/1.7.3
https://roundcube.net/news/2026/08/09/security-updates-1.6.18-and-1.7.3