A vulnerability was discovered by the Pulse Security team. It was
exploitable only when running a non-standard
passenger_instance_registry_dir, via a race condition where after a
file was created, there was a window in which it could be replaced
with a symlink before it was chowned via the path and not the file
descriptor. If the symlink target was to a file which would be
executed by root such as root's crontab file, then privilege
escalation was possible. This is now mitigated by using fchown().
For Debian 8 "Jessie", these problems have been fixed in version
We recommend that you upgrade your ruby-passenger packages.
Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://wiki.debian.org/LTS