Incorrect interaction of the parsepacket() and parsepartsignsha256() functions in network.c in collectd 5.7.1 and earlier allows remote attackers to cause a denial of service (infinite loop) of a collectd instance (configured with "SecurityLevel None" and with empty "AuthFile" options) via a crafted UDP packet.
The csnmpreadtable function in snmp.c in the SNMP plugin in collectd before 5.6.3 is susceptible to a double free in a certain error case, which could lead to a crash (or potentially have other impact).