# CVE-2024-57947: netfilter: nf_set_pipapo: fix initial map fill

> A flaw in the Linux kernel netfilter pipapo algorithm leaks memory bits, potentially allowing attackers to read sensitive kernel memory.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 23 Jan 2025
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2024-57947, DEBIAN-CVE-2024-57947, GHSA-2885-grqh-2673, ROOT-OS-DEBIAN-11-CVE-2024-57947, UBUNTU-CVE-2024-57947

## What is CVE-2024-57947?

CVE-2024-57947 is a critical vulnerability in Linux kernel, published on 23 Jan 2025. 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: nf_set_pipapo: fix initial map fill

The initial buffer has to be inited to all-ones, but it must restrict
it to the size of the first field, not the total field size.

After each round in the map search step, the result and the fill map
are swapped, so if we have a set where f->bsize of the first element
is smaller than m->bsize_max, those one-bits are leaked into future
rounds result map.

This makes pipapo find an incorrect matching results for sets where
first field size is not the largest.

Followup patch adds a test case to nft_concat_range.sh selftest script.

Thanks to Stefano Brivio for pointing out that we need to zero out
the remainder explicitly, only correcting memset() argument isn't enough.

Weakness: CWE-401 (Missing Release of Memory after Effective Lifetime)

## Which versions are affected by CVE-2024-57947?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-57947?

Apply the vendor's patch.

## Is CVE-2024-57947 being exploited?

There is no known exploitation of CVE-2024-57947 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-2024-57947 and fix it if it is affected.

What it is: CVE-2024-57947 is a critical vulnerability in Linux kernel, published on 23 Jan 2025. 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-2024-57947 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-2024-57947/ (Markdown: https://insights.sbomify.com/CVE-2024-57947/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-57947
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-57947
- OSV: https://osv.dev/vulnerability/CVE-2024-57947

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-57947/
Summaries are generated and may contain mistakes; the official description above is the record.