An issue was discovered in the Linux kernel through 5.2.13. nbd_genl_status in drivers/block/nbd.c does not check the nla_nest_start_noflag return value.
Created kernel tracking bugs for this issue:
Affects: fedora-all [bug 1751394]
To mitigate this issue, prevent module nbd from being loaded. Please see https://access.redhat.com/solutions/41278 for how to blacklist a kernel module to prevent it from loading automatically.
The impact of this issue is Low, because attack is specific for certain network block device usage and could be triggered only by local user with access to the device (resulting denial-of-service) and attack is complex, because could happen only if specific condition (out of memory) at the moment of the attack is met.