CVE-2023-39281

Firmware code execution via AsfSecureBootDxe stack overflow

Published Nov 1, 2023 · Updated Sep 6, 2024

Stack buffer overflow in Insyde Software InsydeH2O 5.0 through 5.5 allows local users to execute code in AsfSecureBootDxe during DXE. Insyde identifies the affected driver but has not disclosed which untrusted input or copy operation overruns its stack buffer. Exploitation requires highly privileged local access and high-complexity conditions, with code execution occurring in the firmware DXE phase.

CVSS severity4.1
Medium
EPSS probability0.49%
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 Insyde Software InsydeH2O 5.0 through 5.5 allows local users to execute code in AsfSecureBootDxe during DXE. Insyde identifies the affected driver but has not disclosed which untrusted input or copy operation overruns its stack buffer. Exploitation requires highly privileged local access and high-complexity conditions, with code execution occurring in the firmware DXE phase.

The record

CVE
CVE-2023-39281
Published
Nov 1, 2023
Updated
Sep 6, 2024
Vendor
Insyde Software
Product
InsydeH2O UEFI BIOS
Classifications
CWE-121
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Nov 1, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 6, 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=5.0 <=5.5

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Insyde Software · InsydeH2O UEFI BIOSversion=5.0 <=5.5

Published CVSS scores

5.7CISA ADPCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
4.1Insyde SoftwareCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:N

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-121Stack-based Buffer Overflow

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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