# CVE-2024-40960: ipv6: prevent possible NULL dereference in rt6_probe()

> A NULL pointer dereference in the Linux kernel IPv6 routing code allows attackers to cause a system crash via crafted network traffic.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 12 Jul 2024
- **Updated:** 15 Oct 2026
- **Also known as:** BELL-CVE-2024-40960, DEBIAN-CVE-2024-40960, GHSA-894g-hq68-4qh8, UBUNTU-CVE-2024-40960

## What is CVE-2024-40960?

CVE-2024-40960 is a medium-severity vulnerability in Linux kernel, published on 12 Jul 2024. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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

ipv6: prevent possible NULL dereference in rt6_probe()

syzbot caught a NULL dereference in rt6_probe() [1]

Bail out if  __in6_dev_get() returns NULL.

[1]
Oops: general protection fault, probably for non-canonical address 0xdffffc00000000cb: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000658-0x000000000000065f]
CPU: 1 PID: 22444 Comm: syz-executor.0 Not tainted 6.10.0-rc2-syzkaller-00383-gb8481381d4e2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
 RIP: 0010:rt6_probe net/ipv6/route.c:656 [inline]
 RIP: 0010:find_match+0x8c4/0xf50 net/ipv6/route.c:758
Code: 14 fd f7 48 8b 85 38 ff ff ff 48 c7 45 b0 00 00 00 00 48 8d b8 5c 06 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 19
RSP: 0018:ffffc900034af070 EFLAGS: 00010203
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc90004521000
RDX: 00000000000000cb RSI: ffffffff8990d0cd RDI: 000000000000065c
RBP: ffffc900034af150 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000002 R12: 000000000000000a
R13: 1ffff92000695e18 R14: ffff8880244a1d20 R15: 0000000000000000
FS:  00007f4844a5a6c0(0000) GS:ffff8880b9300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31b27000 CR3: 000000002d42c000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
  rt6_nh_find_match+0xfa/0x1a0 net/ipv6/route.c:784
  nexthop_for_each_fib6_nh+0x26d/0x4a0 net/ipv4/nexthop.c:1496
  __find_rr_leaf+0x6e7/0xe00 net/ipv6/route.c:825
  find_rr_leaf net/ipv6/route.c:853 [inline]
  rt6_select net/ipv6/route.c:897 [inline]
  fib6_table_lookup+0x57e/0xa30 net/ipv6/route.c:2195
  ip6_pol_route+0x1cd/0x1150 net/ipv6/route.c:2231
  pol_lookup_func include/net/ip6_fib.h:616 [inline]
  fib6_rule_lookup+0x386/0x720 net/ipv6/fib6_rules.c:121
  ip6_route_output_flags_noref net/ipv6/route.c:2639 [inline]
  ip6_route_output_flags+0x1d0/0x640 net/ipv6/route.c:2651
  ip6_dst_lookup_tail.constprop.0+0x961/0x1760 net/ipv6/ip6_output.c:1147
  ip6_dst_lookup_flow+0x99/0x1d0 net/ipv6/ip6_output.c:1250
  rawv6_sendmsg+0xdab/0x4340 net/ipv6/raw.c:898
  inet_sendmsg+0x119/0x140 net/ipv4/af_inet.c:853
  sock_sendmsg_nosec net/socket.c:730 [inline]
  __sock_sendmsg net/socket.c:745 [inline]
  sock_write_iter+0x4b8/0x5c0 net/socket.c:1160
  new_sync_write fs/read_write.c:497 [inline]
  vfs_write+0x6b6/0x1140 fs/read_write.c:590
  ksys_write+0x1f8/0x260 fs/read_write.c:643
  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
  do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2024-40960?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-40960?

Apply the vendor's patch.

## Is CVE-2024-40960 being exploited?

There is no known exploitation of CVE-2024-40960 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-40960 and fix it if it is affected.

What it is: CVE-2024-40960 is a medium-severity vulnerability in Linux kernel, published on 12 Jul 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2024-40960 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2024-40960/ (Markdown: https://insights.sbomify.com/CVE-2024-40960/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-40960
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-40960
- OSV: https://osv.dev/vulnerability/CVE-2024-40960

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-40960/
Summaries are generated and may contain mistakes; the official description above is the record.