CVE-2024-56646

/// Technical description

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

ipv6: avoid possible NULL deref in modify_prefix_route()

syzbot found a NULL deref [1] in modify_prefix_route(), caused by one

fib6_info without a fib6_table pointer set.

This can happen for net->ipv6.fib6_null_entry

[1]

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] PREEMPT SMP KASAN NOPTI

KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]

CPU: 1 UID: 0 PID: 5837 Comm: syz-executor888 Not tainted 6.12.0-syzkaller-09567-g7eef7e306d3c #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024

RIP: 0010:__lock_acquire+0xe4/0x3c40 kernel/locking/lockdep.c:5089

Code: 08 84 d2 0f 85 15 14 00 00 44 8b 0d ca 98 f5 0e 45 85 c9 0f 84 b4 0e 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 e2 48 c1 ea 03 <80> 3c 02 00 0f 85 96 2c 00 00 49 8b 04 24 48 3d a0 07 7f 93 0f 84

RSP: 0018:ffffc900035d7268 EFLAGS: 00010006

RAX: dffffc0000

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References