The csnmp_read_table 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).
Incorrect interaction of the parse_packet() and parse_part_sign_sha256() 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.
Heap-based buffer overflow in the parse_packet function in network.c in collectd before 5.4.3 and 5.x before 5.5.2 allows remote attackers to cause a denial of service (daemon crash) or possibly execute arbitrary code via a crafted network packet.