CyberRota Analysis
AI-GeneratedThe vulnerability affects the Linux kernel's IPv4 routing functionality, specifically when the CONFIG_IP_MULTIPLE_TABLES option is enabled without any rules defined. This flaw can lead to the incorrect handling of error routes, allowing a valid route to be overwritten by an erroneous one, potentially disrupting network traffic and causing connectivity issues. System administrators and developers managing Linux environments with multiple routing tables should prioritize addressing this issue to ensure reliable network operations.
Original NVD Description
In the Linux kernel, the following vulnerability has been resolved: ipv4: fib: Don't ignore error route in local/main tables. When CONFIG_IP_MULTIPLE_TABLES is enabled but no rule is added, fib_lookup() performs route lookup directly on two tables. Since the first lookup does not properly bail out, the result of an error route in the merged local/main table could be overwritten by another route in the default table: # unshare -n # ip link set lo up # ip route add 192.168.0.0/24 dev lo table 253 # ip route add unreachable 192.168.0.0/24 # ip route get 192.168.0.1 192.168.0.1 dev lo table default uid 0 cache <local> Once a random rule is added, the error route is respected: # ip rule add table 0 # ip rule del table 0 # ip route get 192.168.0.1 RTNETLINK answers: No route to host Let's fix the inconsistent behaviour.