As reported to the linux-distros mailing list:
libguestfs is a library for accessing and modifying guest disk images.
It was found that guestfish, which enables shell scripting and command
line access to libguestfs, insecurely created the temporary directory
used to store the network socket when started in server mode (using the
"--listen" option). If guestfish were run with the "--listen" option, a
local attacker could use this flaw to intercept and modify other users'
guestfish commands, allowing them to perform arbitrary guestfish actions
(such as modifying virtual machines) with the privileges of a different
user, or use this flaw to obtain authentication credentials.
This issue was discovered by Michael Scherer of the Red Hat Regional IT
Further details are available in our bug, including the patch.
The guestfish command in libguestfs 1.20.12, 1.22.7, and earlier, when using
the --remote or --listen option, does not properly check the ownership of
/tmp/.guestfish-$UID/ when creating a temporary socket file in this
directory, which allows local users to write to the socket and execute
arbitrary commands by creating /tmp/.guestfish-$UID/ in advance.
Maintainer timeout. Cleanup done.