CVE-2022-35895Public exploit

SMM code execution via unchecked SMI parameters

Published Sep 21, 2022 · Updated May 5, 2025

Out-of-bounds write in InsydeH2O kernels 5.0 through 5.5 allows local users with high privileges to execute code in SMM. The FwBlockServiceSmm software-SMI handler fails to validate attacker-controlled parameters before using them to write fixed or predictable data to arbitrary addresses, including SMRAM. Ring-0 access is required; successful exploitation reaches ring -2, bypasses firmware protections, and permits a persistent BIOS implant.

CVSS severity8.2
High
EPSS probability0.36%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in InsydeH2O kernels 5.0 through 5.5 allows local users with high privileges to execute code in SMM. The FwBlockServiceSmm software-SMI handler fails to validate attacker-controlled parameters before using them to write fixed or predictable data to arbitrary addresses, including SMRAM. Ring-0 access is required; successful exploitation reaches ring -2, bypasses firmware protections, and permits a persistent BIOS implant.

The record

CVE
CVE-2022-35895
Published
Sep 21, 2022
Updated
May 5, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787, T1068
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Sep 21, 2022CVE publishedPublication date reported by the CVE source.
  2. May 5, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.2InsydeCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
8.2NVDCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
8.2CISA-ADPCVSS: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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1068Exploitation for Privilege Escalation

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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