# CVE-2023-20540: Information disclosure in AMD Ryzen™ 3000 Series Desktop Processors

> A privileged attacker can exploit timing discrepancies in AMD processors to brute-force HMACs, potentially compromising data integrity.

- **Severity:** Low 1.8 (`CVSS:4.0/AV:L/AC:H/AT:N/PR:H/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 26 Jun 2026
- **Updated:** 26 Jun 2026
- **Also known as:** GHSA-q66m-cmxr-cpcf

## What is CVE-2023-20540?

CVE-2023-20540 is a low-severity vulnerability in AMD Ryzen™ 3000 Series Desktop Processors, published on 26 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

An observable timing discrepancy in the ASP could allow a privileged attacker to perform a brute-force attack against the hash message authentication code, allowing arbitrary message input, potentially leading to a loss of data integrity.

Weakness: CWE-208 (Observable Timing Discrepancy)

## Which versions are affected by CVE-2023-20540?


## How do I fix CVE-2023-20540?

No fix has been published for CVE-2023-20540 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-20540 being exploited?

There is no known exploitation of CVE-2023-20540 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-20540 and fix it if it is affected.

What it is: CVE-2023-20540 is a low-severity vulnerability in AMD Ryzen™ 3000 Series Desktop Processors, published on 26 Jun 2026. 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-2023-20540 in the wild and no public exploit code.

Affected product: AMD Ryzen™ 3000 Series Desktop Processors. 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-2023-20540/ (Markdown: https://insights.sbomify.com/CVE-2023-20540/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-20540
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-20540
- OSV: https://osv.dev/vulnerability/CVE-2023-20540

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From sbomify Insights: https://insights.sbomify.com/CVE-2023-20540/
Summaries are generated and may contain mistakes; the official description above is the record.