CVE-2022-40250Public exploit

SMM code execution via unchecked CopyMem length

Published Sep 20, 2022 · Updated May 28, 2025

Stack-based buffer overflow in Aptio V 5.x allows local users to execute arbitrary code in System Management Mode via a crafted SMI buffer. The SmmSmbiosElog ChildSwSmiHandler passes attacker-controlled Arg4 to CopyMem in ApiFunc1 without bounding it against a 127-byte stack buffer. Low-privileged local access is required; overwriting the return address can modify protected NVRAM, bypass firmware controls, or establish persistent BIOS code.

CVSS severity8.8
High
EPSS probability0.46%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack-based buffer overflow in Aptio V 5.x allows local users to execute arbitrary code in System Management Mode via a crafted SMI buffer. The SmmSmbiosElog ChildSwSmiHandler passes attacker-controlled Arg4 to CopyMem in ApiFunc1 without bounding it against a 127-byte stack buffer. Low-privileged local access is required; overwriting the return address can modify protected NVRAM, bypass firmware controls, or establish persistent BIOS code.

The record

CVE
CVE-2022-40250
Published
Sep 20, 2022
Updated
May 28, 2025
Vendor
American Megatrends International
Product
Aptio V
Classifications
CWE-121, T1068, T1542.001
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 20, 2022CVE publishedPublication date reported by the CVE source.
  2. May 28, 2025Record 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=5.x

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

American Megatrends International · Aptio Vversion=5.x

Published CVSS scores

8.8CISA-ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
8.2BinarlyCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-121Stack-based Buffer Overflow
T1068Exploitation for Privilege Escalation
T1542.001System Firmware

Public exploit references

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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