# CVE-2022-39293: Azure RTOS USBX Host PIMA vulnerable to read integer underflow with buffer overflow

> An integer underflow in Azure RTOS USBX PIMA host class allows attackers to trigger a buffer overflow, potentially leading to code execution or denial of service.

- **Severity:** High 8.6 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 13 Oct 2022
- **Updated:** 23 Apr 2025
- **Also known as:** GHSA-gg76-h537-xq48

## What is CVE-2022-39293?

CVE-2022-39293 is a high-severity vulnerability in azure-rtos usbx, published on 13 Oct 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Azure RTOS USBX is a high-performance USB host, device, and on-the-go (OTG) embedded stack, that is fully integrated with Azure RTOS ThreadX. The case is, in [_ux_host_class_pima_read](https://github.com/azure-rtos/usbx/blob/master/common/usbx_host_classes/src/ux_host_class_pima_read.c), there is data length from device response, returned in the very first packet, and read by [L165 code](https://github.com/azure-rtos/usbx/blob/082fd9db09a3669eca3358f10b8837a5c1635c0b/common/usbx_host_classes/src/ux_host_class_pima_read.c#L165), as header_length. Then in [L178 code](https://github.com/azure-rtos/usbx/blob/082fd9db09a3669eca3358f10b8837a5c1635c0b/common/usbx_host_classes/src/ux_host_class_pima_read.c#L178), there is a “if” branch, which check the expression of “(header_length - UX_HOST_CLASS_PIMA_DATA_HEADER_SIZE) > data_length” where if header_length is smaller than UX_HOST_CLASS_PIMA_DATA_HEADER_SIZE, calculation could overflow and then [L182 code](https://github.com/azure-rtos/usbx/blob/082fd9db09a3669eca3358f10b8837a5c1635c0b/common/usbx_host_classes/src/ux_host_class_pima_read.c#L182) the calculation of data_length is also overflow, this way the later [while loop start from L192](https://github.com/azure-rtos/usbx/blob/082fd9db09a3669eca3358f10b8837a5c1635c0b/common/usbx_host_classes/src/ux_host_class_pima_read.c#L192) can move data_pointer to unexpected address and cause write buffer overflow. The fix has been included in USBX release [6.1.12](https://github.com/azure-rtos/usbx/releases/tag/v6.1.12_rel). The following can be used as a workaround: Add check of `header_length`: 1. It must be greater than `UX_HOST_CLASS_PIMA_DATA_HEADER_SIZE`. 1. It should be greater or equal to the current returned data length (`transfer_request -> ux_transfer_request_actual_length`).

Weakness: CWE-191 (Integer Underflow (Wrap or Wraparound))

## Which versions are affected by CVE-2022-39293?

It affects 1 product.


Products: Eclipse Threadx Usbx.

## How do I fix CVE-2022-39293?

No fix has been published for CVE-2022-39293 yet. Limit exposure of the affected software until one is available.

## Is CVE-2022-39293 being exploited?

There is no known exploitation of CVE-2022-39293 in the wild and no public exploit code.

## Other vulnerabilities in azure-rtos usbx

- [CVE-2022-29246](https://insights.sbomify.com/CVE-2022-29246/): Potential buffer overflow in function DFU upload in Azure RTOS USBX (critical 9.8)
- [CVE-2022-36063](https://insights.sbomify.com/CVE-2022-36063/): USBX Host CDC ECM integer underflow with buffer overflow (high 7.6)
- [CVE-2022-29223](https://insights.sbomify.com/CVE-2022-29223/): Buffer overflow on HUB descriptor in Azure RTOS USBX (high 7.5)
- [CVE-2023-48695](https://insights.sbomify.com/CVE-2023-48695/): Azure RTOS USBX Remote Code Execution Vulnerability (high 7.2)
- [CVE-2023-48694](https://insights.sbomify.com/CVE-2023-48694/): Azure RTOS USBX Remote Code Execution Vulnerability (medium 6.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-39293 and fix it if it is affected.

What it is: CVE-2022-39293 is a high-severity vulnerability in azure-rtos usbx, published on 13 Oct 2022. 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-2022-39293 in the wild and no public exploit code.

Affected product: azure-rtos usbx. 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-2022-39293/ (Markdown: https://insights.sbomify.com/CVE-2022-39293/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-39293
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-39293
- OSV: https://osv.dev/vulnerability/CVE-2022-39293

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-39293/
Summaries are generated and may contain mistakes; the official description above is the record.