Linux kernel IPv4 ICMP out-of-range reply type access

The vulnerability is remotely reachable over the network and can be triggered without privileges or user interaction. Based on the provided scoring and advisory context, the primary impact is high availability impact, with possible kernel instability or denial of service resulting from the out-of-range array access logic in the IPv4 ICMP subsystem. The provided CVSS context also indicates low confidentiality impact and no integrity impact.

If immediate patching is not possible, reduce exposure of vulnerable systems to untrusted network-originated ICMP traffic, especially where extended echo handling may be reachable. Apply network filtering or rate limiting for ICMP where operationally feasible, and restrict direct network exposure of affected hosts. These are compensating controls only; the provided content indicates patching the kernel is the definitive fix.

Upgrade to a Linux kernel release that includes the fix for CVE-2026-46037. The remediation is to validate the ICMP reply type before consulting icmp_pointers[], skip the table lookup for reply types outside the valid range, and use array_index_nospec() for valid in-range accesses. Vendor kernel updates were published across multiple stable and SUSE-supported branches, including fixes referenced by upstream stable commits such as 92e7c209036dcc0e8ffdf806fdfd3645b263bea5, bc64a66e0b9ad937d3d49934242ee62b01ba9a94, c2178ff1c70ebfc2ab9651b230c58a34683db759, d700c34a5d186b9ba0715bcb19e0ff80ffbfbfc1, 67bf002a2d7387a6312138210d0bd06e3cf4879b, b3a88fc5ae024d43c5ecf653f3bbe837e4a6dc99, and 93df2af4f491de33827550b9d420f01808c0706b. Apply the relevant vendor advisory updates for affected distributions.