Input validation error in Roundcube Webmail - #VU132217
Published: May 25, 2026
Vulnerability identifier: #VU132217
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: N/A
CWE-ID: CWE-20
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Roundcube
Affected software:
Roundcube Webmail
Roundcube Webmail
Detailed vulnerability description
The vulnerability allows a remote attacker to cause remote images to be loaded despite blocking restrictions.
The vulnerability exists due to improper input validation in remote image blocking logic when processing CSS var() constructs. A remote attacker can supply specially crafted content using CSS var() to cause remote images to be loaded despite blocking restrictions.
Remediation
Install security update from vendor's website.