An issue was discovered in the Linux kernel through 5.9.1, as used with Xen through 4.14.x. drivers/xen/events/events_base.c allows event-channel removal during the event-handling loop (a race condition). This can cause a use-after-free or NULL pointer dereference, as demonstrated by a dom0 crash via events for an in-reconfiguration paravirtualized device, aka CID-073d0552ead5.
4.4.0-198.2304.4.0-1119.1334.15.0-1091.96~16.04.14.15.0-1103.114~16.04.14.15.0-1091.104~16.04.14.15.0-129.132~16.04.14.10.0-14.16~16.04.14.10.0-19.21~16.04.14.10.0-20.22~16.04.14.10.0-21.23~16.04.14.10.0-22.24~16.04.14.10.0-24.28~16.04.14.10.0-26.30~16.04.14.11.0-13.19~16.04.14.11.0-14.20~16.04.14.13.0-16.19~16.04.3+13 more4.4.0-1085.944.15.0-1062.68~16.04.14.4.0-1143.153Exploitability
AV:LAC:HPR:LUI:NScope
S:UImpact
C:NI:NA:HCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H