CVE-2023-20555

SMM code execution via unchecked pointer bit write

Published Aug 8, 2023 · Updated Oct 24, 2024

Memory corruption in CpmDisplayFeatureSmm on affected AMD processors allows local users to execute arbitrary code in SMM. The SMM driver insufficiently validates an attacker-controlled pointer before overwriting an arbitrary bit at that address. Local low-privileged access is required, and successful exploitation compromises firmware-level execution beneath the operating system.

CVSS severity7.8
High
EPSS probability0.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory corruption in CpmDisplayFeatureSmm on affected AMD processors allows local users to execute arbitrary code in SMM. The SMM driver insufficiently validates an attacker-controlled pointer before overwriting an arbitrary bit at that address. Local low-privileged access is required, and successful exploitation compromises firmware-level execution beneath the operating system.

The record

CVE
CVE-2023-20555
Published
Aug 8, 2023
Updated
Oct 24, 2024
Vendor
AMD
Product
Ryzen 7020 Series Mobile Processors (Mendocino)
Classifications
CWE-787, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 8, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 24, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

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 · Ryzen 7020 Series Mobile Processors (Mendocino)version=various
AMD · Ryzen 5000 Series Mobile Processors with Radeon Graphics (Lucienne)version=various
AMD · Ryzen 3000 Series Desktop Processors (Matisse)version=various
AMD · Ryzen 4000 Series Desktop Processors with Radeon Graphicsversion=1.2.0.A
AMD · Ryzen 5000 Series Desktop Processor with Radeon Graphics (Cezanne) AM4version=various
AMD · Athlon 3000 Series Mobile Processors with Radeon Graphics (Pollock)version=various
AMD · Ryzen 4000 Series Desktop Processors with Radeon Graphics (Renoir)version=various
AMD · Ryzen 5000 Series Desktop Processors (Vermeer)version=various
AMD · Ryzen 7000 Series Processors (Raphael)version=various
AMD · Athlon 3000 Series Desktop Processors with Radeon Graphics (Picasso)version=various
AMD · AMD Ryzen 7000 Series Desktop Processors (Raphael)version=1.0.0.6
AMD · Ryzen 4000 Series Mobile Processors with Radeon Graphics (Renoir)version=various
AMD · Ryzen 5000 Series Mobile Processors with Radeon Graphics (Cezanne)version=various
AMD · Ryzen 5000 Series Desktop Processorsversion=V2-PI_1.2.0.A
AMD · Ryzen 6000 Series Mobile Processors (Rembrandt)version=various
AMD · Ryzen 7030 Series Mobile Processors (Barcelo)version=various
AMD · Ryzen 3000 Series Desktop Processorsversion=V1-1.0.0.A
AMD · Athlon 3000 Series Mobile Processors with Radeon Graphics (Dali/Dali FP5)version=various
AMD · Ryzen 3000 Series Mobile Processors with Radeon Graphics (Picasso)version=various
AMD · AMD Athlon 3000Gversion=1.0.0.A; version=1.2.0.A

Published CVSS scores

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.

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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
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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