# CVE-2026-43114: netfilter: nft_set_pipapo_avx2: don't return non-matching entry on expiry

> A logic error in the Linux kernel's AVX2 netfilter implementation causes incorrect set matching, leading to false positive duplicate entry errors during set reloads.

- **Severity:** Critical 9.4 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 6 May 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-43114, DEBIAN-CVE-2026-43114, GHSA-6cwp-88hv-x237, ROOT-OS-DEBIAN-11-CVE-2026-43114, ROOT-OS-DEBIAN-12-CVE-2026-43114, ROOT-OS-UBUNTU-2204-CVE-2026-43114, ROOT-OS-UBUNTU-2404-CVE-2026-43114, UBUNTU-CVE-2026-43114

## What is CVE-2026-43114?

CVE-2026-43114 is a critical vulnerability in Linux kernel, published on 6 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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

netfilter: nft_set_pipapo_avx2: don't return non-matching entry on expiry

New test case fails unexpectedly when avx2 matching functions are used.

The test first loads a ranomly generated pipapo set
with 'ipv4 . port' key, i.e.  nft -f foo.

This works.  Then, it reloads the set after a flush:
(echo flush set t s; cat foo) | nft -f -

This is expected to work, because its the same set after all and it was
already loaded once.

But with avx2, this fails: nft reports a clashing element.

The reported clash is of following form:

    We successfully re-inserted
      a . b
      c . d

Then we try to insert a . d

avx2 finds the already existing a . d, which (due to 'flush set') is marked
as invalid in the new generation.  It skips the element and moves to next.

Due to incorrect masking, the skip-step finds the next matching
element *only considering the first field*,

i.e. we return the already reinserted "a . b", even though the
last field is different and the entry should not have been matched.

No such error is reported for the generic c implementation (no avx2) or when
the last field has to use the 'nft_pipapo_avx2_lookup_slow' fallback.

Bisection points to
7711f4bb4b36 ("netfilter: nft_set_pipapo: fix range overlap detection")
but that fix merely uncovers this bug.

Before this commit, the wrong element is returned, but erronously
reported as a full, identical duplicate.

The root-cause is too early return in the avx2 match functions.
When we process the last field, we should continue to process data
until the entire input size has been consumed to make sure no stale
bits remain in the map.

Weakness: CWE-480 (Use of Incorrect Operator), CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2026-43114?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-43114?

Apply the vendor's patch.

## Is CVE-2026-43114 being exploited?

There is no known exploitation of CVE-2026-43114 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-2026-43114 and fix it if it is affected.

What it is: CVE-2026-43114 is a critical vulnerability in Linux kernel, published on 6 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-43114 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-2026-43114/ (Markdown: https://insights.sbomify.com/CVE-2026-43114/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43114
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43114
- OSV: https://osv.dev/vulnerability/CVE-2026-43114

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43114/
Summaries are generated and may contain mistakes; the official description above is the record.