A vulnerability was discovered in Linux, FreeBSD, OpenBSD, MacOS, iOS, and Android that allows a malicious access point, or an adjacent user, to determine if a connected user is using a VPN, make positive inferences about the websites they are visiting, and determine the correct sequence and acknowledgement numbers in use, allowing the bad actor to inject data into the TCP stream. This provides everything that is needed for an attacker to hijack active connections inside the VPN tunnel.

lmp_print_data_link_subobjs() in print-lmp.c in tcpdump before 4.9.3 lacks certain bounds checks.

The SMB parser in tcpdump before 4.9.3 has buffer over-reads in print-smb.c:print_trans() for \MAILSLOT\BROWSE and \PIPE\LANMAN.

The BGP parser in tcpdump before 4.9.3 has a buffer over-read in print-bgp.c:bgp_attr_print() (MP_REACH_NLRI).

The DCCP parser in tcpdump before 4.9.3 has a buffer over-read in print-dccp.c:dccp_print_option().

The HNCP parser in tcpdump before 4.9.3 has a buffer over-read in print-hncp.c:print_prefix().

The IEEE 802.11 parser in tcpdump before 4.9.3 has a buffer over-read in print-802_11.c for the Mesh Flags subfield.

The ICMPv6 parser in tcpdump before 4.9.3 has a buffer over-read in print-icmp6.c.

The BGP parser in tcpdump before 4.9.3 has a buffer over-read in print-bgp.c:bgp_capabilities_print() (BGP_CAPCODE_RESTART).

The OSPFv3 parser in tcpdump before 4.9.3 has a buffer over-read in print-ospf6.c:ospf6_print_lshdr().

The command-line argument parser in tcpdump before 4.9.3 has a buffer overflow in tcpdump.c:get_next_file().

The Babel parser in tcpdump before 4.9.3 has a buffer over-read in print-babel.c:babel_print_v2().

The IKEv1 parser in tcpdump before 4.9.3 has a buffer over-read in print-isakmp.c:ikev1_n_print().

The FRF.16 parser in tcpdump before 4.9.3 has a buffer over-read in print-fr.c:mfr_print().

The BGP parser in tcpdump before 4.9.3 has a buffer over-read in print-bgp.c:bgp_capabilities_print() (BGP_CAPCODE_MP).

The Rx parser in tcpdump before 4.9.3 has a buffer over-read in print-rx.c:rx_cache_find() and rx_cache_insert().

The RSVP parser in tcpdump before 4.9.3 has a buffer over-read in print-rsvp.c:rsvp_obj_print().

The LMP parser in tcpdump before 4.9.3 has a buffer over-read in print-lmp.c:lmp_print_data_link_subobjs().

The VRRP parser in tcpdump before 4.9.3 has a buffer over-read in print-vrrp.c:vrrp_print() for VRRP version 2, a different vulnerability than CVE-2019-15167.

The ICMP parser in tcpdump before 4.9.3 has a buffer over-read in print-icmp.c:icmp_print().