# CVE-2025-38441: netfilter: flowtable: account for Ethernet header in nf_flow_pppoe_proto()

> A missing Ethernet header check in the Linux kernel netfilter flowtable allows attackers to read uninitialized memory, potentially leaking sensitive kernel data.

- **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:** 25 Jul 2025
- **Updated:** 23 May 2026
- **Also known as:** AZL-72920, BELL-CVE-2025-38441, DEBIAN-CVE-2025-38441, GHSA-h35g-vvhp-7ww4, ROOT-OS-UBUNTU-2204-CVE-2025-38441, ROOT-OS-UBUNTU-2404-CVE-2025-38441, UBUNTU-CVE-2025-38441

## What is CVE-2025-38441?

CVE-2025-38441 is a medium-severity vulnerability in Debian Debian Linux, published on 25 Jul 2025. 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: flowtable: account for Ethernet header in nf_flow_pppoe_proto()

syzbot found a potential access to uninit-value in nf_flow_pppoe_proto()

Blamed commit forgot the Ethernet header.

BUG: KMSAN: uninit-value in nf_flow_offload_inet_hook+0x7e4/0x940 net/netfilter/nf_flow_table_inet.c:27
  nf_flow_offload_inet_hook+0x7e4/0x940 net/netfilter/nf_flow_table_inet.c:27
  nf_hook_entry_hookfn include/linux/netfilter.h:157 [inline]
  nf_hook_slow+0xe1/0x3d0 net/netfilter/core.c:623
  nf_hook_ingress include/linux/netfilter_netdev.h:34 [inline]
  nf_ingress net/core/dev.c:5742 [inline]
  __netif_receive_skb_core+0x4aff/0x70c0 net/core/dev.c:5837
  __netif_receive_skb_one_core net/core/dev.c:5975 [inline]
  __netif_receive_skb+0xcc/0xac0 net/core/dev.c:6090
  netif_receive_skb_internal net/core/dev.c:6176 [inline]
  netif_receive_skb+0x57/0x630 net/core/dev.c:6235
  tun_rx_batched+0x1df/0x980 drivers/net/tun.c:1485
  tun_get_user+0x4ee0/0x6b40 drivers/net/tun.c:1938
  tun_chr_write_iter+0x3e9/0x5c0 drivers/net/tun.c:1984
  new_sync_write fs/read_write.c:593 [inline]
  vfs_write+0xb4b/0x1580 fs/read_write.c:686
  ksys_write fs/read_write.c:738 [inline]
  __do_sys_write fs/read_write.c:749 [inline]

Weakness: CWE-908 (Use of Uninitialized Resource)

## Which versions are affected by CVE-2025-38441?

It affects 2 products.


Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2025-38441?

Apply the vendor's patch.

## Is CVE-2025-38441 being exploited?

There is no known exploitation of CVE-2025-38441 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-38441 and fix it if it is affected.

What it is: CVE-2025-38441 is a medium-severity vulnerability in Debian Debian Linux, published on 25 Jul 2025. 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-2025-38441 in the wild and no public exploit code.

Affected product: Debian Debian Linux. 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-2025-38441/ (Markdown: https://insights.sbomify.com/CVE-2025-38441/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-38441
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-38441
- OSV: https://osv.dev/vulnerability/CVE-2025-38441

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-38441/
Summaries are generated and may contain mistakes; the official description above is the record.