# CVE-2026-43450: netfilter: nfnetlink_cthelper: fix OOB read in nfnl_cthelper_dump_table()

> A local attacker can trigger an out-of-bounds read in the Linux kernel netfilter subsystem, potentially leaking memory or causing a system crash.

- **Severity:** High 7.1 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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:** 8 May 2026
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2026-43450, DEBIAN-CVE-2026-43450, GHSA-4jv3-xpmj-f4vf, ROOT-OS-DEBIAN-11-CVE-2026-43450, ROOT-OS-UBUNTU-2204-CVE-2026-43450, ROOT-OS-UBUNTU-2404-CVE-2026-43450, UBUNTU-CVE-2026-43450

## What is CVE-2026-43450?

CVE-2026-43450 is a high-severity memory corruption vulnerability in Linux kernel, published on 8 May 2026. 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:

netfilter: nfnetlink_cthelper: fix OOB read in nfnl_cthelper_dump_table()

nfnl_cthelper_dump_table() has a 'goto restart' that jumps to a label
inside the for loop body.  When the "last" helper saved in cb->args[1]
is deleted between dump rounds, every entry fails the (cur != last)
check, so cb->args[1] is never cleared.  The for loop finishes with
cb->args[0] == nf_ct_helper_hsize, and the 'goto restart' jumps back
into the loop body bypassing the bounds check, causing an 8-byte
out-of-bounds read on nf_ct_helper_hash[nf_ct_helper_hsize].

The 'goto restart' block was meant to re-traverse the current bucket
when "last" is no longer found, but it was placed after the for loop
instead of inside it.  Move the block into the for loop body so that
the restart only occurs while cb->args[0] is still within bounds.

 BUG: KASAN: slab-out-of-bounds in nfnl_cthelper_dump_table+0x9f/0x1b0
 Read of size 8 at addr ffff888104ca3000 by task poc_cthelper/131
 Call Trace:
  nfnl_cthelper_dump_table+0x9f/0x1b0
  netlink_dump+0x333/0x880
  netlink_recvmsg+0x3e2/0x4b0
  sock_recvmsg+0xde/0xf0
  __sys_recvfrom+0x150/0x200
  __x64_sys_recvfrom+0x76/0x90
  do_syscall_64+0xc3/0x6e0

 Allocated by task 1:
  __kvmalloc_node_noprof+0x21b/0x700
  nf_ct_alloc_hashtable+0x65/0xd0
  nf_conntrack_helper_init+0x21/0x60
  nf_conntrack_init_start+0x18d/0x300
  nf_conntrack_standalone_init+0x12/0xc0

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-43450?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-43450?

Apply the vendor's patch.

## Is CVE-2026-43450 being exploited?

There is no known exploitation of CVE-2026-43450 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-2026-43450 and fix it if it is affected.

What it is: CVE-2026-43450 is a high-severity memory corruption vulnerability in Linux kernel, published on 8 May 2026. 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-2026-43450 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-2026-43450/ (Markdown: https://insights.sbomify.com/CVE-2026-43450/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43450
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43450
- OSV: https://osv.dev/vulnerability/CVE-2026-43450

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43450/
Summaries are generated and may contain mistakes; the official description above is the record.