In the AppleTalk subsystem in the Linux kernel before 5.1, there is a potential NULL pointer dereference because register_snap_client may return NULL. This will lead to denial of service in net/appletalk/aarp.c and net/appletalk/ddp.c, as demonstrated by unregister_snap_client, aka CID-9804501fa122.
5.13.0-19.196.11.0-8.85.3.0-18.195.3.0-24.265.4.0-9.123.11.0-12.193.12.0-1.33.12.0-2.53.12.0-2.73.12.0-3.83.12.0-3.93.12.0-4.103.12.0-4.123.12.0-5.133.12.0-7.15+170 more4.2.0-16.194.2.0-17.214.2.0-19.234.3.0-1.104.3.0-2.114.3.0-5.164.3.0-6.174.3.0-7.184.4.0-10.254.4.0-101.124+94 more4.4.0-173.2034.13.0-16.194.13.0-17.204.13.0-25.294.13.0-32.354.15.0-10.114.15.0-12.134.15.0-13.144.15.0-15.164.15.0-19.204.15.0-20.21+34 more4.15.0-88.886.5.0-9.94.4.0-1001.104.4.0-1003.124.4.0-1004.134.4.0-1007.164.4.0-1009.184.4.0-1011.204.4.0-1012.214.4.0-1013.224.4.0-1016.254.4.0-1017.26+52 more4.4.0-1101.1124.4.0-1002.24.4.0-1003.34.4.0-1005.54.4.0-1006.64.4.0-1009.94.4.0-1010.104.4.0-1011.114.4.0-1012.124.4.0-1014.144.4.0-1016.16+25 more6.5.0-1008.8Exploitability
AV:LAC:LPR:LUI:NScope
S:UImpact
C:NI:NA:HCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H