# CVE-2022-49872: net: gso: fix panic on frag_list with mixed head alloc types

> A logic error in the Linux kernel network stack causes a kernel panic when processing fragmented packets with mixed allocation types, leading to denial of service.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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:** 1 May 2025
- **Updated:** 5 Aug 2026
- **Also known as:** DEBIAN-CVE-2022-49872, GHSA-v832-47wf-r9vp, UBUNTU-CVE-2022-49872

## What is CVE-2022-49872?

CVE-2022-49872 is a high-severity vulnerability in Linux kernel, published on 1 May 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:

net: gso: fix panic on frag_list with mixed head alloc types

Since commit 3dcbdb134f32 ("net: gso: Fix skb_segment splat when
splitting gso_size mangled skb having linear-headed frag_list"), it is
allowed to change gso_size of a GRO packet. However, that commit assumes
that "checking the first list_skb member suffices; i.e if either of the
list_skb members have non head_frag head, then the first one has too".

It turns out this assumption does not hold. We've seen BUG_ON being hit
in skb_segment when skbs on the frag_list had differing head_frag with
the vmxnet3 driver. This happens because __netdev_alloc_skb and
__napi_alloc_skb can return a skb that is page backed or kmalloced
depending on the requested size. As the result, the last small skb in
the GRO packet can be kmalloced.

There are three different locations where this can be fixed:

(1) We could check head_frag in GRO and not allow GROing skbs with
    different head_frag. However, that would lead to performance
    regression on normal forward paths with unmodified gso_size, where
    !head_frag in the last packet is not a problem.

(2) Set a flag in bpf_skb_net_grow and bpf_skb_net_shrink indicating
    that NETIF_F_SG is undesirable. That would need to eat a bit in
    sk_buff. Furthermore, that flag can be unset when all skbs on the
    frag_list are page backed. To retain good performance,
    bpf_skb_net_grow/shrink would have to walk the frag_list.

(3) Walk the frag_list in skb_segment when determining whether
    NETIF_F_SG should be cleared. This of course slows things down.

This patch implements (3). To limit the performance impact in
skb_segment, the list is walked only for skbs with SKB_GSO_DODGY set
that have gso_size changed. Normal paths thus will not hit it.

We could check only the last skb but since we need to walk the whole
list anyway, let's stay on the safe side.

## Which versions are affected by CVE-2022-49872?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2022-49872?

Apply the vendor's patch.

## Is CVE-2022-49872 being exploited?

There is no known exploitation of CVE-2022-49872 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-2022-49872 and fix it if it is affected.

What it is: CVE-2022-49872 is a high-severity vulnerability in Linux kernel, published on 1 May 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-2022-49872 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-2022-49872/ (Markdown: https://insights.sbomify.com/CVE-2022-49872/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-49872
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-49872
- OSV: https://osv.dev/vulnerability/CVE-2022-49872

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-49872/
Summaries are generated and may contain mistakes; the official description above is the record.