# CVE-2026-98131: net: stmmac: fix dma mapping leak in stmmac_tso_xmit()

> A DMA mapping leak in the stmmac network driver allows attackers to exhaust system resources, causing a denial of service.

- **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 Sep 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-104856, BELL-CVE-2026-98131, DEBIAN-CVE-2026-98131, GHSA-m77g-747m-3xxc, UBUNTU-CVE-2026-98131

## What is CVE-2026-98131?

CVE-2026-98131 is a medium-severity denial of service vulnerability in Linux kernel, published on 25 Sep 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:

net: stmmac: fix dma mapping leak in stmmac_tso_xmit()

In stmmac_tso_xmit(), if the DMA mapping of an skb fragment fails, the
frame is dropped but the DMA mappings already created for the linear
part and for the fragments mapped before the failure are never
unmapped, leaking DMA mappings.

Fix the leak by walking back over the descriptors used by the frame and
releasing each of them with stmmac_free_tx_buffer(). Moreover, release
the descriptors with stmmac_release_tx_desc() unmapping the DMA buffers.

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

## Which versions are affected by CVE-2026-98131?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-98131?

Apply the vendor's patch.

## Is CVE-2026-98131 being exploited?

There is no known exploitation of CVE-2026-98131 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-2026-98131 and fix it if it is affected.

What it is: CVE-2026-98131 is a medium-severity denial of service vulnerability in Linux kernel, published on 25 Sep 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-2026-98131 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-2026-98131/ (Markdown: https://insights.sbomify.com/CVE-2026-98131/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98131
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98131
- OSV: https://osv.dev/vulnerability/CVE-2026-98131

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98131/
Summaries are generated and may contain mistakes; the official description above is the record.