CVE-2022-35897

Arbitrary code execution via reused GetVariable size

Published Nov 21, 2022 · Updated Apr 30, 2025

Stack buffer overflow in InsydeH2O kernel 5.0 through 5.5 allows physically proximate attackers to execute arbitrary code during DXE. The BdsDxe function initializes DataSize only before the first of three GetVariable calls, so one variable enlarges it and the next call overwrites a one-byte stack buffer and the return address. Exploitation requires physical SPI-flash access to alter at least two normally read-only UEFI variables and yields firmware-level code execution that can persist across an operating-system boot.

CVSS severity7.6
High
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack buffer overflow in InsydeH2O kernel 5.0 through 5.5 allows physically proximate attackers to execute arbitrary code during DXE. The BdsDxe function initializes DataSize only before the first of three GetVariable calls, so one variable enlarges it and the next call overwrites a one-byte stack buffer and the return address. Exploitation requires physical SPI-flash access to alter at least two normally read-only UEFI variables and yields firmware-level code execution that can persist across an operating-system boot.

The record

CVE
CVE-2022-35897
Published
Nov 21, 2022
Updated
Apr 30, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787, T1542.001
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 21, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 30, 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 vectorphysical
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.6Insyde SoftwareCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
6.8NIST NVDCVSS:3.1/AV:P/AC:L/PR:N/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)
Vectorphysical
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1542.001System Firmware

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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