# CVE-2023-52796: ipvlan: add ipvlan_route_v6_outbound() helper

> A stack overflow in the Linux kernel ipvlan driver can cause a system crash when processing IPv6 outbound traffic with stacked devices.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:** 21 May 2024
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2023-52796, DEBIAN-CVE-2023-52796, GHSA-68x5-x32c-8c8w, UBUNTU-CVE-2023-52796

## What is CVE-2023-52796?

CVE-2023-52796 is a high-severity denial of service vulnerability in Linux kernel, published on 21 May 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:

ipvlan: add ipvlan_route_v6_outbound() helper

Inspired by syzbot reports using a stack of multiple ipvlan devices.

Reduce stack size needed in ipvlan_process_v6_outbound() by moving
the flowi6 struct used for the route lookup in an non inlined
helper. ipvlan_route_v6_outbound() needs 120 bytes on the stack,
immediately reclaimed.

Also make sure ipvlan_process_v4_outbound() is not inlined.

We might also have to lower MAX_NEST_DEV, because only syzbot uses
setups with more than four stacked devices.

BUG: TASK stack guard page was hit at ffffc9000e803ff8 (stack is ffffc9000e804000..ffffc9000e808000)
stack guard page: 0000 [#1] SMP KASAN
CPU: 0 PID: 13442 Comm: syz-executor.4 Not tainted 6.1.52-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
RIP: 0010:kasan_check_range+0x4/0x2a0 mm/kasan/generic.c:188
Code: 48 01 c6 48 89 c7 e8 db 4e c1 03 31 c0 5d c3 cc 0f 0b eb 02 0f 0b b8 ea ff ff ff 5d c3 cc 00 00 cc cc 00 00 cc cc 55 48 89 e5 <41> 57 41 56 41 55 41 54 53 b0 01 48 85 f6 0f 84 a4 01 00 00 48 89
RSP: 0018:ffffc9000e804000 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff817e5bf2
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff887c6568
RBP: ffffc9000e804000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92001d0080c
R13: dffffc0000000000 R14: ffffffff87e6b100 R15: 0000000000000000
FS: 00007fd0c55826c0(0000) GS:ffff8881f6800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffc9000e803ff8 CR3: 0000000170ef7000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<#DF>
</#DF>
<TASK>
[<ffffffff81f281d1>] __kasan_check_read+0x11/0x20 mm/kasan/shadow.c:31
[<ffffffff817e5bf2>] instrument_atomic_read include/linux/instrumented.h:72 [inline]
[<ffffffff817e5bf2>] _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
[<ffffffff817e5bf2>] cpumask_test_cpu include/linux/cpumask.h:506 [inline]
[<ffffffff817e5bf2>] cpu_online include/linux/cpumask.h:1092 [inline]
[<ffffffff817e5bf2>] trace_lock_acquire include/trace/events/lock.h:24 [inline]
[<ffffffff817e5bf2>] lock_acquire+0xe2/0x590 kernel/locking/lockdep.c:5632
[<ffffffff8563221e>] rcu_lock_acquire+0x2e/0x40 include/linux/rcupdate.h:306
[<ffffffff8561464d>] rcu_read_lock include/linux/rcupdate.h:747 [inline]
[<ffffffff8561464d>] ip6_pol_route+0x15d/0x1440 net/ipv6/route.c:2221
[<ffffffff85618120>] ip6_pol_route_output+0x50/0x80 net/ipv6/route.c:2606
[<ffffffff856f65b5>] pol_lookup_func include/net/ip6_fib.h:584 [inline]
[<ffffffff856f65b5>] fib6_rule_lookup+0x265/0x620 net/ipv6/fib6_rules.c:116
[<ffffffff85618009>] ip6_route_output_flags_noref+0x2d9/0x3a0 net/ipv6/route.c:2638
[<ffffffff8561821a>] ip6_route_output_flags+0xca/0x340 net/ipv6/route.c:2651
[<ffffffff838bd5a3>] ip6_route_output include/net/ip6_route.h:100 [inline]
[<ffffffff838bd5a3>] ipvlan_process_v6_outbound drivers/net/ipvlan/ipvlan_core.c:473 [inline]
[<ffffffff838bd5a3>] ipvlan_process_outbound drivers/net/ipvlan/ipvlan_core.c:529 [inline]
[<ffffffff838bd5a3>] ipvlan_xmit_mode_l3 drivers/net/ipvlan/ipvlan_core.c:602 [inline]
[<ffffffff838bd5a3>] ipvlan_queue_xmit+0xc33/0x1be0 drivers/net/ipvlan/ipvlan_core.c:677
[<ffffffff838c2909>] ipvlan_start_xmit+0x49/0x100 drivers/net/ipvlan/ipvlan_main.c:229
[<ffffffff84d03900>] netdev_start_xmit include/linux/netdevice.h:4966 [inline]
[<ffffffff84d03900>] xmit_one net/core/dev.c:3644 [inline]
[<ffffffff84d03900>] dev_hard_start_xmit+0x320/0x980 net/core/dev.c:3660
[<ffffffff84d080e2>] __dev_queue_xmit+0x16b2/0x3370 net/core/dev.c:4324
[<ffffffff855ce4cd>] dev_queue_xmit include/linux/netdevice.h:3067 [inline]
[<ffffffff855ce4cd>] neigh_hh_output include/net/neighbour.h:529 [inline]
[<f
---truncated---

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2023-52796?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2023-52796?

Apply the vendor's patch.

## Is CVE-2023-52796 being exploited?

There is no known exploitation of CVE-2023-52796 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-2023-52796 and fix it if it is affected.

What it is: CVE-2023-52796 is a high-severity denial of service vulnerability in Linux kernel, published on 21 May 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-2023-52796 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-2023-52796/ (Markdown: https://insights.sbomify.com/CVE-2023-52796/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-52796
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-52796
- OSV: https://osv.dev/vulnerability/CVE-2023-52796

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-52796/
Summaries are generated and may contain mistakes; the official description above is the record.