# CVE-2026-43373: net: ncsi: fix skb leak in error paths

> A memory leak in the Linux kernel NCSI driver allows attackers to cause denial of service by triggering error paths that fail to release network buffers.

- **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:** 8 May 2026
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2026-43373, DEBIAN-CVE-2026-43373, GHSA-cc5x-4c4f-8gxf, ROOT-OS-DEBIAN-11-CVE-2026-43373, ROOT-OS-UBUNTU-2204-CVE-2026-43373, ROOT-OS-UBUNTU-2404-CVE-2026-43373, UBUNTU-CVE-2026-43373

## What is CVE-2026-43373?

CVE-2026-43373 is a high-severity denial of service vulnerability in Linux kernel, published on 8 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:

net: ncsi: fix skb leak in error paths

Early return paths in NCSI RX and AEN handlers fail to release
the received skb, resulting in a memory leak.

Specifically, ncsi_aen_handler() returns on invalid AEN packets
without consuming the skb. Similarly, ncsi_rcv_rsp() exits early
when failing to resolve the NCSI device, response handler, or
request, leaving the skb unfreed.

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

## Which versions are affected by CVE-2026-43373?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-43373?

Apply the vendor's patch.

## Is CVE-2026-43373 being exploited?

There is no known exploitation of CVE-2026-43373 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-2026-43373 and fix it if it is affected.

What it is: CVE-2026-43373 is a high-severity denial of service vulnerability in Linux kernel, published on 8 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-2026-43373 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-2026-43373/ (Markdown: https://insights.sbomify.com/CVE-2026-43373/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43373
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43373
- OSV: https://osv.dev/vulnerability/CVE-2026-43373

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43373/
Summaries are generated and may contain mistakes; the official description above is the record.