Linux Kernel Data-Race Vulnerability in IPv4 Multipath Neighbor Handling

A data-race vulnerability has been identified in the Linux kernel's IPv4 handling of multipath routing, specifically around the sysctl_fib_multipath_use_neigh parameter. This vulnerability arises because the parameter can be changed concurrently while it is being read, leading to potential inconsistencies. The issue has been addressed by adding a READ_ONCE() directive to the parameter's reader.

Impact

Exploitation of this vulnerability could lead to a data race condition, causing inconsistent behavior in the routing decision process that relies on the sysctl_fib_multipath_use_neigh parameter.