An issue was discovered in Mutt before 1.10.1 and NeoMutt before 2018-07-16. They allow remote IMAP servers to execute arbitrary commands via backquote characters, related to the mailboxes command associated with an automatic subscription.
Created mutt tracking bugs for this issue:
Affects: fedora-all [bug 1602916]
This issue has been addressed in the following products:
Red Hat Enterprise Linux 6
Red Hat Enterprise Linux 7
Via RHSA-2018:2526 https://access.redhat.com/errata/RHSA-2018:2526