CRLF injection in Roundcube Webmail - #VU156153
Published: October 19, 2026
Vulnerability identifier: #VU156153
CSH Severity: Low
CVSS v4: 4.6 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/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 attacker to inject mail headers into a message forwarded as an attachment.
The vulnerability exists due to improper neutralization of header delimiters in attachment forwarding when processing the subject of the forwarded message. A remote attacker can supply a message with a crafted subject and induce a user to forward it as an attachment to introduce additional mail headers or alter header interpretation.
Affected software
Roundcube Webmail
Remediation
Install security update from vendor's website.
Roundcube Webmail - addressed in versions 1.6.20, 1.7.5