CRLF injection in Roundcube Webmail - #VU162691
Published: November 9, 2026
Vulnerability identifier: #VU162691
CSH Severity: Low
CVSS v4: 5.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-93
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to inject unintended IMAP commands.
The vulnerability exists due to insufficient neutralization of carriage return and line feed characters in Roundcube Webmail's _uid parameter handling when constructing IMAP commands. A remote user can submit an _uid value containing CRLF characters to introduce additional commands into the IMAP exchange.
Exploitation requires messages_cache to be enabled.
Affected software
Roundcube Webmail
Remediation
Install security update from vendor's website.
Roundcube Webmail - addressed in versions 1.6.21, 1.7.6