CVE-2026-46266: inet: RAW sockets using IPPROTO_RAW MUST drop incoming ICMP

CVE-2026-46266: inet: RAW sockets using IPPROTO_RAW MUST drop incoming ICMP

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

inet: RAW sockets using IPPROTO_RAW MUST drop incoming ICMP

Yizhou Zhao reported that simply having one RAW socket on protocol
IPPROTO_RAW (255) was dangerous.

  socket(AF_INET, SOCK_RAW, 255);

A malicious incoming ICMP packet can set the protocol field to 255
and match this socket, leading to FNHE cache changes.

inner = IP(src="192.168.2.1", dst="8.8.8.8", proto=255)/Raw("TEST")
pkt = IP(src="192.168.1.1", dst="192.168.2.1")/ICMP(type=3, code=4, nexthopmtu=576)/inner

"man 7 raw" states:

  A protocol of IPPROTO_RAW implies enabled IP_HDRINCL and is able
  to send any IP protocol that is specified in the passed header.
  Receiving of all IP protocols via IPPROTO_RAW is not possible
  using raw sockets.

Make sure we drop these malicious packets.

The Linux kernel CVE team has assigned CVE-2026-46266 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.6.128 with commit db76b75ede3810e7cf9cfea5067d4f3e0993768b
	Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.12.75 with commit 19e42490c89bac9a388f28179e66bebbef350f99
	Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.18.14 with commit 531c1aec81bfe19d00af13da5531fbb8209e4bd2
	Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.19.4 with commit 719d3932b8f6e3348ce2f0ac58e278301fc17575
	Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 7.0 with commit c89477ad79446867394360b29bb801010fc3ff22

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-46266
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	net/ipv4/icmp.c
	net/ipv6/icmp.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/db76b75ede3810e7cf9cfea5067d4f3e0993768b
	https://git.kernel.org/stable/c/19e42490c89bac9a388f28179e66bebbef350f99
	https://git.kernel.org/stable/c/531c1aec81bfe19d00af13da5531fbb8209e4bd2
	https://git.kernel.org/stable/c/719d3932b8f6e3348ce2f0ac58e278301fc17575
	https://git.kernel.org/stable/c/c89477ad79446867394360b29bb801010fc3ff22