CVE-2026-45847: net: remove WARN_ON_ONCE when accessing forward path array

CVE-2026-45847: net: remove WARN_ON_ONCE when accessing forward path array

[Greg Kroah-Hartman]

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

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

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

net: remove WARN_ON_ONCE when accessing forward path array

Although unlikely, recent support for IPIP tunnels increases chances of
reaching this WARN_ON_ONCE if userspace manages to build a sufficiently
long forward path.

Remove it.

The Linux kernel CVE team has assigned CVE-2026-45847 to this issue.


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

	Issue introduced in 5.13 with commit ddb94eafab8b597b05904c8277194ea2d6357fa9 and fixed in 5.15.202 with commit 548244c2f542aa0ad49453e9306e715a3877bc44
	Issue introduced in 5.13 with commit ddb94eafab8b597b05904c8277194ea2d6357fa9 and fixed in 6.1.165 with commit dcf9b3c90e5560339649d088836529883fb509f3
	Issue introduced in 5.13 with commit ddb94eafab8b597b05904c8277194ea2d6357fa9 and fixed in 6.6.128 with commit 9464ca7a6e56ad1ebf48b2ad5c16871edfad10c6
	Issue introduced in 5.13 with commit ddb94eafab8b597b05904c8277194ea2d6357fa9 and fixed in 6.12.75 with commit 959ea349c7e2d4edf07b6838ca7e59345fe61a08
	Issue introduced in 5.13 with commit ddb94eafab8b597b05904c8277194ea2d6357fa9 and fixed in 6.18.14 with commit 50422613185d505201167e8bdd2f2700790d5db6
	Issue introduced in 5.13 with commit ddb94eafab8b597b05904c8277194ea2d6357fa9 and fixed in 6.19.4 with commit a78d055ba7c31103ad02f8eceb0c452e154d2660
	Issue introduced in 5.13 with commit ddb94eafab8b597b05904c8277194ea2d6357fa9 and fixed in 7.0 with commit 008e7a7c293b30bc43e4368dac6ea3808b75a572

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-2026-45847
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/core/dev.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/548244c2f542aa0ad49453e9306e715a3877bc44
	https://git.kernel.org/stable/c/dcf9b3c90e5560339649d088836529883fb509f3
	https://git.kernel.org/stable/c/9464ca7a6e56ad1ebf48b2ad5c16871edfad10c6
	https://git.kernel.org/stable/c/959ea349c7e2d4edf07b6838ca7e59345fe61a08
	https://git.kernel.org/stable/c/50422613185d505201167e8bdd2f2700790d5db6
	https://git.kernel.org/stable/c/a78d055ba7c31103ad02f8eceb0c452e154d2660
	https://git.kernel.org/stable/c/008e7a7c293b30bc43e4368dac6ea3808b75a572