CVE-2022-4020

Secure Boot bypass via unchecked NVRAM variable

Published Nov 28, 2022 · Updated Apr 14, 2025

Improper permissions in five Acer notebook models with BIOS 1.04 through 1.10 allow local users with administrative access to disable Secure Boot. The HQSwSmiDxe DXE driver checks only whether BootOrderSecureBootDisable exists and disables Secure Boot without validating its value. Administrative OS access is required to create the variable; disabling Secure Boot permits an unsigned malicious bootloader to control OS startup.

CVSS severity8.1
High
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper permissions in five Acer notebook models with BIOS 1.04 through 1.10 allow local users with administrative access to disable Secure Boot. The HQSwSmiDxe DXE driver checks only whether BootOrderSecureBootDisable exists and disables Secure Boot without validating its value. Administrative OS access is required to create the variable; disabling Secure Boot permits an unsigned malicious bootloader to control OS startup.

The record

CVE
CVE-2022-4020
Published
Nov 28, 2022
Updated
Apr 14, 2025
Vendor
Acer Inc.
Product
Extensa EX215-21G
Classifications
CWE-276, T1542.003
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Nov 28, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 14, 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=1.04 <1.11

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Acer Inc. · Extensa EX215-21Gversion=1.04 <1.11
Acer Inc. · Aspire A315-22version=1.04 <1.11
Acer Inc. · Extensa EX215-21version=1.04 <1.11
Acer Inc. · Aspire A115-21version=1.04 <1.11
Acer Inc. · Aspire A315-22Gversion=1.04 <1.11

Published CVSS scores

8.2NIST NVDCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
8.1ESETCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:L/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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-276Incorrect Default Permissions
T1542.003Pre-OS Boot: Bootkit

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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