CVE-2023-26299

Firmware code execution via SMI handler race

Published Jun 30, 2023 · Updated Dec 4, 2024

A TOCTOU race in AMI UEFI firmware on affected HP PCs allows local users with low privileges to execute arbitrary code in firmware. Vulnerable SMI handlers validate shared-memory data before use, but DMA timing can alter that data between validation and use, bypassing the check. Exploitation requires local low-privileged access, user interaction, and precise timing; successful code runs beneath the operating system in SMM.

CVSS severity7.5
High
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

A TOCTOU race in AMI UEFI firmware on affected HP PCs allows local users with low privileges to execute arbitrary code in firmware. Vulnerable SMI handlers validate shared-memory data before use, but DMA timing can alter that data between validation and use, bypassing the check. Exploitation requires local low-privileged access, user interaction, and precise timing; successful code runs beneath the operating system in SMM.

The record

CVE
CVE-2023-26299
Published
Jun 30, 2023
Updated
Dec 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-367, CAPEC-29, T1542.001
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 30, 2023CVE publishedPublication date reported by the CVE source.
  2. Dec 4, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5HP Inc.CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H
7.0NIST NVDCVSS:3.1/AV:L/AC:H/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-367Time-of-check Time-of-use (TOCTOU) Race Condition
CAPEC-29Leveraging Time-of-Check and Time-of-Use (TOCTOU) Race Conditions
T1542.001Pre-OS Boot: System 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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo