CVE-2021-21573

Arbitrary code execution via recovery image overflow

Published Jun 24, 2021 · Updated Sep 17, 2024

Buffer overflow in Dell BIOSConnect before Gen 11, Gen 10 allows local users to run arbitrary code via crafted recovery content. The overflow occurs while BIOSConnect processes downloaded OS-recovery or firmware-update data in the pre-boot environment. Exploitation requires an authenticated administrator with local access and a physically present user invoking BIOSConnect; successful code execution can bypass UEFI restrictions and control boot-time code.

CVSS severity7.2
High
EPSS probability0.28%
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

Buffer overflow in Dell BIOSConnect before Gen 11, Gen 10 allows local users to run arbitrary code via crafted recovery content. The overflow occurs while BIOSConnect processes downloaded OS-recovery or firmware-update data in the pre-boot environment. Exploitation requires an authenticated administrator with local access and a physically present user invoking BIOSConnect; successful code execution can bypass UEFI restrictions and control boot-time code.

The record

CVE
CVE-2021-21573
Published
Jun 24, 2021
Updated
Sep 17, 2024
Vendor
Dell
Product
BIOSConnect
Classifications
CWE-121, CWE-787, T1203
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Jun 24, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 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?

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

  1. Affected versionversion=unspecified <Gen 11, Gen 10

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Dell · BIOSConnectversion=unspecified <Gen 11, Gen 10

Published CVSS scores

7.5NVDCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H
7.2DellCVSS:3.1/AV:L/AC:H/PR:H/UI:R/S:C/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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-121Stack-based Buffer Overflow
CWE-787Out-of-bounds Write
T1203Exploitation for Client Execution

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