Squid security advisory 2016:5 reports:
Due to incorrect buffer management Squid cachemgr.cgi tool is
vulnerable to a buffer overflow when processing remotely supplied
inputs relayed to it from Squid.
This problem allows any client to seed the Squid manager reports
with data that will cause a buffer overflow when processed by the
cachemgr.cgi tool. However, this does require manual administrator
actions to take place. Which greatly reduces the impact and
possible uses.
Squid security advisory 2016:6 reports:
Due to buffer overflow issues Squid is vulnerable to a denial of
service attack when processing ESI responses. Due to incorrect input
validation Squid is vulnerable to public information disclosure of
the server stack layout when processing ESI responses. Due to
incorrect input validation and buffer overflow Squid is vulnerable
to remote code execution when processing ESI responses.
These problems allow ESI components to be used to perform a denial
of service attack on the Squid service and all other services on the
same machine. Under certain build conditions these problems allow
remote clients to view large sections of the server memory. However,
the bugs are exploitable only if you have built and configured the
ESI features to be used by a reverse-proxy and if the ESI components
being processed by Squid can be controlled by an attacker.