CVE-2018-19518: Canonical Ubuntu Linux

High severity, CVSS 7.5. EPSS: 96.1% chance of exploitation in the next 30 days.

University of Washington IMAP Toolkit 2007f on UNIX, as used in imap_open() in PHP and other products, launches an rsh command (by means of the imap_rimap function in c-client/imap4r1.c and the tcp_aopen function in osdep/unix/tcp_unix.c) without preventing argument injection, which might allow remote attackers to execute arbitrary OS commands if the IMAP server name is untrusted input (e.g., entered by a user of a web application) and if rsh has been replaced by a program with different argument semantics. For example, if rsh is a link to ssh (as seen on Debian and Ubuntu systems), then the attack can use an IMAP server name containing a "-oProxyCommand" argument.

Affected products

• Canonical Ubuntu Linux: version 16.04 only; version 18.04 only; version 19.04 only
• Debian Debian Linux: version 8.0 only; version 9.0 only
• PHP PHP: from 5.6.0, up to and including 5.6.38; from 7.0.0, up to and including 7.0.32; from 7.1.0, up to and including 7.1.24; from 7.2.0, up to and including 7.2.12
• Uw-Imap Project Uw-Imap: version 2007f only

Published 2018-11-25. Last modified 2026-06-17.