CVE-2021-3661

Local code execution via undisclosed UEFI flaw

Published Nov 21, 2022 · Updated Apr 29, 2025

Code injection in HP Workstation BIOS allows local users to execute arbitrary code through an unspecified UEFI firmware flaw. HP has not published the affected firmware locus or the operation that mishandles attacker-controlled input. Exploitation requires local access, and successful code execution can compromise confidentiality, integrity, and system availability.

CVSS severity8.1
High
EPSS probability0.32%
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

Code injection in HP Workstation BIOS allows local users to execute arbitrary code through an unspecified UEFI firmware flaw. HP has not published the affected firmware locus or the operation that mishandles attacker-controlled input. Exploitation requires local access, and successful code execution can compromise confidentiality, integrity, and system availability.

The record

CVE
CVE-2021-3661
Published
Nov 21, 2022
Updated
Apr 29, 2025
Vendor
Plantronics
Product
HP Workstation BIOS
Classifications
CWE-94
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 21, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 29, 2025Record 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=See HP Security Bulletin reference for affected versions.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Plantronics · HP Workstation BIOSversion=See HP Security Bulletin reference for affected versions.

Published CVSS scores

8.1HP Inc.CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
8.4CISA-ADPCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
8.4NIST NVDCVSS:3.1/AV:L/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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')

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