Stack-based buffer overflow in the bgp_route_refresh_receive function in bgp_packet.c in bgpd in Quagga before 0.99.17 allows remote authenticated users to cause a denial of service (daemon crash) or possibly execute arbitrary code via a malformed Outbound Route Filtering (ORF) record in a BGP ROUTE-REFRESH (RR) message.

bgpd in Quagga before 0.99.17 does not properly parse AS paths, which allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via an unknown AS type in an AS path attribute in a BGP UPDATE message.

The BGP daemon (bgpd) in Quagga 0.99.11 and earlier allows remote attackers to cause a denial of service (crash) via an AS path containing ASN elements whose string representation is longer than expected, which triggers an assert error.

bgpd in Quagga before 0.99.9 allows explicitly configured BGP peers to cause a denial of service (crash) via a malformed (1) OPEN message or (2) a COMMUNITY attribute, which triggers a NULL pointer dereference. NOTE: vector 2 only exists when debugging is enabled.

bgpd/bgp_attr.c in Quagga 0.98.6 and earlier, and 0.99.6 and earlier 0.99 versions, does not validate length values in the MP_REACH_NLRI and MP_UNREACH_NLRI attributes, which allows remote attackers to cause a denial of service (daemon crash or exit) via crafted UPDATE messages that trigger an assertion error or out of bounds read.

RIPd in Quagga 0.98 and 0.99 before 20060503 does not properly enforce RIPv2 authentication requirements, which allows remote attackers to modify routing state via RIPv1 RESPONSE packets.

The vty layer in Quagga before 0.96.4, and Zebra 0.93b and earlier, does not verify that sub-negotiation is taking place when processing the SE marker, which allows remote attackers to cause a denial of service (crash) via a malformed telnet command to the telnet CLI port, which may trigger a null dereference.