In Wireshark 2.2.0 to 2.2.3 and 2.0.0 to 2.0.9, the DHCPv6 dissector could go into a large loop, triggered by packet injection or a malformed capture file. This was addressed in epan/dissectors/packet-dhcpv6.c by changing a data type to avoid an integer overflow.
Exploitability
AV:NAC:LPR:NUI:NScope
S:UImpact
C:NI:NA:H7.5/CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H