CVE-2021-46758

Integrity loss via out-of-range SPI reads

Published Nov 14, 2023 · Updated Aug 4, 2024

Improper address validation in AMD Ryzen ASP bootloader firmware allows physically proximate attackers to cause integrity loss or service interruption. The bootloader accepts SPI flash addresses beyond the flash boundary and reads adjacent memory-mapped regions instead of rejecting them. Physical access to an affected x86 platform is required; successful exploitation can compromise integrity or interrupt startup, with no reported confidentiality impact.

CVSS severity6.1
Medium
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper address validation in AMD Ryzen ASP bootloader firmware allows physically proximate attackers to cause integrity loss or service interruption. The bootloader accepts SPI flash addresses beyond the flash boundary and reads adjacent memory-mapped regions instead of rejecting them. Physical access to an affected x86 platform is required; successful exploitation can compromise integrity or interrupt startup, with no reported confidentiality impact.

The record

CVE
CVE-2021-46758
Published
Nov 14, 2023
Updated
Aug 4, 2024
Vendor
AMD
Product
AMD Ryzen 7035 Series Processors with Radeon Graphics (Rembrandt-R)
Classifications
Unavailable
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 14, 2023CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=various

What conditions does exploitation require?

Attack vectorphysical
Required privilegesunauthenticated

What is affected?

AMD · AMD Ryzen 7035 Series Processors with Radeon Graphics (Rembrandt-R)version=various
AMD · Ryzen 5000 Series Mobile Processors with Radeon Graphics (Lucienne)version=various
AMD · AMD Ryzen 4000 Series Mobile Processors with Radeon Graphics (Renoir FP6)version=various
AMD · AMD Ryzen 6000 Series Processors with Radeon Graphics (Rembrandt)version=various
AMD · AMD Ryzen 7000 Series Desktop Processors (Raphael XD3)version=various
AMD · Ryzen 5000 Series Mobile Processors with Radeon Graphics (Cezanne)version=various
AMD · AMD Ryzen 5000 Series Processors with Radeon Graphics (Barcelo)version=various
AMD · AMD Ryzen 5000 Series Desktop Processors with Radeon Graphics (Cezanne)version=various
AMD · AMD Ryzen 7030 Series Mobile Processors with Radeon Graphics (Barcelo-R)version=various

Published CVSS scores

6.1NIST NVDCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorphysical
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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