# CVE-2021-46778: Information disclosure in AMD Processors

> Attackers can leak sensitive information by measuring scheduler contention on AMD Zen CPUs using simultaneous multithreading.

- **Severity:** Medium 5.6 (`CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N`)
- **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:** No
- **Published:** 9 Aug 2022
- **Updated:** 17 Sep 2024
- **Also known as:** GHSA-745h-3gvr-9mc6

## What is CVE-2021-46778?

CVE-2021-46778 is a medium-severity vulnerability in Amd Epyc 7232p Firmware, published on 9 Aug 2022. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Execution unit scheduler contention may lead to a side channel vulnerability found on AMD CPU microarchitectures codenamed “Zen 1”, “Zen 2” and “Zen 3” that use simultaneous multithreading (SMT). By measuring the contention level on scheduler queues an attacker may potentially leak sensitive information.

Weakness: CWE-203 (Observable Discrepancy)

## Which versions are affected by CVE-2021-46778?

It affects 179 products.


Products: Amd Athlon 3050ge Firmware, Amd Athlon 3150g Firmware, Amd Athlon 3150ge Firmware, Amd Epyc 7001 Firmware, Amd Epyc 7002 Firmware, Amd Epyc 7003 Firmware, Amd Epyc 7232p Firmware, Amd Epyc 7251 Firmware, Amd Epyc 7252 Firmware, Amd Epyc 7261 Firmware, Amd Epyc 7262 Firmware, Amd Epyc 7272 Firmware, Amd Epyc 7281 Firmware, Amd Epyc 7282 Firmware, Amd Epyc 72f3 Firmware, Amd Epyc 7301 Firmware, Amd Epyc 7302 Firmware, Amd Epyc 7302p Firmware, Amd Epyc 7313 Firmware, Amd Epyc 7313p Firmware and 159 more.

## How do I fix CVE-2021-46778?

No fix has been published for CVE-2021-46778 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-46778 being exploited?

There is no known exploitation of CVE-2021-46778 in the wild and no public exploit code.

## Other vulnerabilities in Amd Epyc 7232p Firmware

- [CVE-2021-26316](https://insights.sbomify.com/CVE-2021-26316/): Memory corruption in 1st Gen EPYC (high 7.8)
- [CVE-2021-26317](https://insights.sbomify.com/CVE-2021-26317/): Security feature bypass in Athlon™ Series (high 7.8)
- [CVE-2021-26369](https://insights.sbomify.com/CVE-2021-26369/): Memory corruption in Athlon™ Series (high 7.8)
- [CVE-2020-12965](https://insights.sbomify.com/CVE-2020-12965/): Information disclosure in All supported processors (high 7.5)
- [CVE-2021-26362](https://insights.sbomify.com/CVE-2021-26362/): Privilege escalation in Athlon™ Series (high 7.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-46778 and fix it if it is affected.

What it is: CVE-2021-46778 is a medium-severity vulnerability in Amd Epyc 7232p Firmware, published on 9 Aug 2022. 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-2021-46778 in the wild and no public exploit code.

Affected product: Amd Epyc 7232p Firmware. 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-2021-46778/ (Markdown: https://insights.sbomify.com/CVE-2021-46778/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-46778
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-46778
- OSV: https://osv.dev/vulnerability/CVE-2021-46778

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-46778/
Summaries are generated and may contain mistakes; the official description above is the record.