# CVE-2021-46755: Denial of service in 3rd Gen AMD Ryzen™ Threadripper™ Processors “Castle Peak” HEDT

> A malicious bootloader can exhaust SysHub resources in AMD Secure Processor, causing denial of service on affected Ryzen processors.

- **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:** No
- **Published:** 9 May 2023
- **Updated:** 28 Jan 2025
- **Also known as:** GHSA-xpf2-4v7h-fpcm

## What is CVE-2021-46755?

CVE-2021-46755 is a high-severity denial of service vulnerability in 3rd Gen AMD Ryzen™ Threadripper™ Processors “Castle Peak” HEDT, published on 9 May 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Failure to unmap certain SysHub mappings in
error paths of the ASP (AMD Secure Processor) bootloader may allow an attacker
with a malicious bootloader to exhaust the SysHub resources resulting in a
potential denial of service.

## Which versions are affected by CVE-2021-46755?

It affects 23 products.


Products: Amd Ryzen 3100 Firmware, Amd Ryzen 3300x Firmware, Amd Ryzen 3500 Firmware, Amd Ryzen 3500x Firmware, Amd Ryzen 3600 Firmware, Amd Ryzen 3600x Firmware, Amd Ryzen 3600xt Firmware, Amd Ryzen 3800x Firmware, Amd Ryzen 3800xt Firmware, Amd Ryzen 3900 Firmware, Amd Ryzen 3900x Firmware, Amd Ryzen 3900xt Firmware, Amd Ryzen 3950x Firmware, Amd Ryzen 5500 Firmware, Amd Ryzen 5600 Firmware, Amd Ryzen 5600g Firmware, Amd Ryzen 5600x Firmware, Amd Ryzen 5700g Firmware, Amd Ryzen 5700x Firmware, Amd Ryzen 5800x3d Firmware and 3 more.

## How do I fix CVE-2021-46755?

No fix has been published for CVE-2021-46755 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-46755 being exploited?

There is no known exploitation of CVE-2021-46755 in the wild and no public exploit code.

## Other vulnerabilities in 3rd Gen AMD Ryzen™ Threadripper™ Processors “Castle Peak” HEDT

- [CVE-2021-46765](https://insights.sbomify.com/CVE-2021-46765/): Denial of service in Ryzen™ 3000 Series Mobile Processors with Radeon™ Graphics “Renoir” (high 7.5)
- [CVE-2023-20597](https://insights.sbomify.com/CVE-2023-20597/): Information disclosure in AMD EPYC™ Embedded 7003 (medium 5.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-46755 and fix it if it is affected.

What it is: CVE-2021-46755 is a high-severity denial of service vulnerability in 3rd Gen AMD Ryzen™ Threadripper™ Processors “Castle Peak” HEDT, published on 9 May 2023. 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-2021-46755 in the wild and no public exploit code.

Affected product: 3rd Gen AMD Ryzen™ Threadripper™ Processors “Castle Peak” HEDT. 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-2021-46755/ (Markdown: https://insights.sbomify.com/CVE-2021-46755/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-46755
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-46755
- OSV: https://osv.dev/vulnerability/CVE-2021-46755

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-46755/
Summaries are generated and may contain mistakes; the official description above is the record.