# CVE-2022-50709: wifi: ath9k: avoid uninit memory read in ath9k_htc_rx_msg()

> A local attacker with physical access or USB privileges can trigger an uninitialized memory read in the ath9k WiFi driver, potentially leaking kernel memory contents.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Dec 2025
- **Updated:** 11 May 2026
- **Also known as:** DEBIAN-CVE-2022-50709, GHSA-cpm8-mrmc-3w57, UBUNTU-CVE-2022-50709

## What is CVE-2022-50709?

CVE-2022-50709 is a vulnerability in Linux, published on 24 Dec 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:

wifi: ath9k: avoid uninit memory read in ath9k_htc_rx_msg()

syzbot is reporting uninit value at ath9k_htc_rx_msg() [1], for
ioctl(USB_RAW_IOCTL_EP_WRITE) can call ath9k_hif_usb_rx_stream() with
pkt_len = 0 but ath9k_hif_usb_rx_stream() uses
__dev_alloc_skb(pkt_len + 32, GFP_ATOMIC) based on an assumption that
pkt_len is valid. As a result, ath9k_hif_usb_rx_stream() allocates skb
with uninitialized memory and ath9k_htc_rx_msg() is reading from
uninitialized memory.

Since bytes accessed by ath9k_htc_rx_msg() is not known until
ath9k_htc_rx_msg() is called, it would be difficult to check minimal valid
pkt_len at "if (pkt_len > 2 * MAX_RX_BUF_SIZE) {" line in
ath9k_hif_usb_rx_stream().

We have two choices. One is to workaround by adding __GFP_ZERO so that
ath9k_htc_rx_msg() sees 0 if pkt_len is invalid. The other is to let
ath9k_htc_rx_msg() validate pkt_len before accessing. This patch chose
the latter.

Note that I'm not sure threshold condition is correct, for I can't find
details on possible packet length used by this protocol.

## Which versions are affected by CVE-2022-50709?


## How do I fix CVE-2022-50709?

Apply the vendor's patch.

## Is CVE-2022-50709 being exploited?

There is no known exploitation of CVE-2022-50709 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-50709 and fix it if it is affected.

What it is: CVE-2022-50709 is a vulnerability in Linux, published on 24 Dec 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-2022-50709 in the wild and no public exploit code.

Affected product: 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-2022-50709/ (Markdown: https://insights.sbomify.com/CVE-2022-50709/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-50709
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-50709
- OSV: https://osv.dev/vulnerability/CVE-2022-50709

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-50709/
Summaries are generated and may contain mistakes; the official description above is the record.