CVE-2021-26335

Arbitrary code execution via unchecked boot image header

Published Nov 16, 2021 · Updated Sep 16, 2024

Improper input validation in the AMD Secure Processor boot loader on various AMD Ryzen and Athlon processors allows local users to execute code. The boot loader uses attacker-controlled image-header values before validating the image signature because it does not adequately check their input and ranges. Low-privileged local access is required, and successful exploitation executes arbitrary code in the ASP security processor.

CVSS severity7.8
High
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in the AMD Secure Processor boot loader on various AMD Ryzen and Athlon processors allows local users to execute code. The boot loader uses attacker-controlled image-header values before validating the image signature because it does not adequately check their input and ranges. Low-privileged local access is required, and successful exploitation executes arbitrary code in the ASP security processor.

The record

CVE
CVE-2021-26335
Published
Nov 16, 2021
Updated
Sep 16, 2024
Vendor
AMD
Product
AMD Ryzen Series
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 16, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 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 vectorlocal
Required privilegesauthenticated

What is affected?

AMD · AMD Ryzen Seriesversion=various
AMD · AMD Athlon Seriesversion=various

Published CVSS scores

7.2NIST NVDAV:L/AC:L/Au:N/C:C/I:C/A:C
7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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.

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No observations available

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

Weakness, pattern, technique

T1068Exploitation for Privilege Escalation

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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