# 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, potential…

CVE record · `CVE-2023-20540`

- **Identifiers:** `CVE-2023-20540`
- **State:** Confirmed
- **Severity:** CVSS 1.8 Low
- **Critical:** No
- **CNA:** AMD
- **Weakness (CWE):** [CWE-208](https://cwe.mitre.org/data/definitions/208.html)
- **Tags:** [CWE-208](https://agentprime.io/advisories/tag/cwe-208.md)
- **Technologies:** [AMD Ryzen™ 3000 Series Desktop Processors](https://agentprime.io/advisories/technology/amd-ryzentm-3000-series-desktop-processors.md) · [AMD Ryzen™ 5000 Series Desktop Processors](https://agentprime.io/advisories/technology/amd-ryzentm-5000-series-desktop-processors.md) · [AMD Ryzen™ Threadripper™ 3000 Series Processors](https://agentprime.io/advisories/technology/amd-ryzentm-threadrippertm-3000-series-processors.md) · [AMD Ryzen™ Threadripper™ PRO 3000WX Series Processors](https://agentprime.io/advisories/technology/amd-ryzentm-threadrippertm-pro-3000wx-series-processors.md) · [AMD Ryzen™ Threadripper™ PRO 5000 WX-Series Processors](https://agentprime.io/advisories/technology/amd-ryzentm-threadrippertm-pro-5000-wx-series-processors.md)
- **Published:** 26 Jun 2026
- **Updated:** 26 Jun 2026
- **Reviewed by a person:** No

Published by the CVE Program (CNA: AMD) at 26 Jun 2026, 15:44 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it.

## Affected products, as the CNA wrote them

- Vendor: AMD. Product: AMD Ryzen™ 3000 Series Desktop Processors.
  - unaffected: `ComboAM4 1.0.0.E`
  - unaffected: `ComboAM4v2PI 1.2.0.CA`
  - Other versions: affected
- Vendor: AMD. Product: AMD Ryzen™ 5000 Series Desktop Processors.
  - unaffected: `ComboAM4v2PI 1.2.0.CA`
  - Other versions: affected
- Vendor: AMD. Product: AMD Ryzen™ Threadripper™ 3000 Series Processors.
  - unaffected: `CastlePeakPI-SP3r3 1.0.0.C`
  - Other versions: affected
- Vendor: AMD. Product: AMD Ryzen™ Threadripper™ PRO 3000WX Series Processors.
  - unaffected: `CastlePeakWSPI-sWRX8 1.0.0.E`
  - Other versions: affected
- Vendor: AMD. Product: AMD Ryzen™ Threadripper™ PRO 5000 WX-Series Processors.
  - unaffected: `ChagallWSPI-sWRX8 1.0.0.9`
  - Other versions: affected

## Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

## Severity and exploitation

- 1.8 Low, CVSS 4.0: `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`, from CNA (AMD)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0015, the 4th percentile, on 6 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

This record came from the full history of the CVE Program, published 26 Jun 2026. New records show when each source confirmed them.

## Sources

- [CVE List: CVE-2023-20540](https://www.cve.org/CVERecord?id=CVE-2023-20540)
- [NVD: CVE-2023-20540](https://nvd.nist.gov/vuln/detail/CVE-2023-20540)

### References from the CNA

- <https://www.amd.com/en/resources/product-security/bulletin/amd-sb-4012.html>

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.

## Check whether this affects you

This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it. Compare the affected versions above with what you run.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), `get_advisory` returns this record and `search_advisories` finds related ones. Setup: <https://agentprime.io/mcp.md>
- As JSON: <https://api.agentprime.io/v1/advisories/CVE-2023-20540>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2023-20540/>. Everything for agents: <https://agentprime.io/llms.txt>.