An issue was discovered in Quagga through 1.2.4. Unsafe chown/chmod operations in the suggested spec file allow users (with control of the non-root-owned directory /etc/quagga) to escalate their privileges to root upon package installation or update.

The Quagga BGP daemon (bgpd) prior to version 1.2.3 has a bug in its parsing of "Capabilities" in BGP OPEN messages, in the bgp_packet.c:bgp_capability_msg_parse function. The parser can enter an infinite loop on invalid capabilities if a Multi-Protocol capability does not have a recognized AFI/SAFI, causing a denial of service.

The Quagga BGP daemon (bgpd) prior to version 1.2.3 can overrun internal BGP code-to-string conversion tables used for debug by 1 pointer value, based on input.

The Quagga BGP daemon (bgpd) prior to version 1.2.3 can double-free memory when processing certain forms of UPDATE message, containing cluster-list and/or unknown attributes. A successful attack could cause a denial of service or potentially allow an attacker to execute arbitrary code.

The Quagga BGP daemon (bgpd) prior to version 1.2.3 does not properly bounds check the data sent with a NOTIFY to a peer, if an attribute length is invalid. Arbitrary data from the bgpd process may be sent over the network to a peer and/or bgpd may crash.

The aspath_put function in bgpd/bgp_aspath.c in Quagga before 1.2.2 allows remote attackers to cause a denial of service (session drop) via BGP UPDATE messages, because AS_PATH size calculation for long paths counts certain bytes twice and consequently constructs an invalid message.

It was discovered that the zebra daemon in Quagga before 1.0.20161017 suffered from a stack-based buffer overflow when processing IPv6 Neighbor Discovery messages. The root cause was relying on BUFSIZ to be compatible with a message size; however, BUFSIZ is system-dependent.

All versions of Quagga, 0.93 through 1.1.0, are vulnerable to an unbounded memory allocation in the telnet 'vty' CLI, leading to a Denial-of-Service of Quagga daemons, or even the entire host. When Quagga daemons are configured with their telnet CLI enabled, anyone who can connect to the TCP ports can trigger this vulnerability, prior to authentication. Most distributions restrict the Quagga telnet interface to local access only by default. The Quagga telnet interface 'vty' input buffer grows automatically, without bound, so long as a newline is not entered. This allows an attacker to cause the Quagga daemon to allocate unbounded memory by sending very long strings without a newline. Eventually the daemon is terminated by the system, or the system itself runs out of memory. This is fixed in Quagga 1.1.1 and Free Range Routing (FRR) Protocol Suite 2017-01-10.

Stack-based buffer overflow in the new_msg_lsa_change_notify function in the OSPFD API (ospf_api.c) in Quagga before 0.99.22.2, when --enable-opaque-lsa and the -a command line option are used, allows remote attackers to cause a denial of service (crash) via a large LSA.

The bgp_capability_orf function in bgpd in Quagga 0.99.20.1 and earlier allows remote attackers to cause a denial of service (assertion failure and daemon exit) by leveraging a BGP peering relationship and sending a malformed Outbound Route Filtering (ORF) capability TLV in an OPEN message.