CVE-2021-21554

Local code execution via BIOS stack overflow

Published Jun 14, 2021 · Updated Sep 16, 2024

Stack-based buffer overflow in Dell PowerEdge BIOS before 2.9.4 allows local users with high privileges to cause denial of service, execute code, or disclose information in the UEFI or BIOS preboot environment. The vulnerable firmware path mishandles Intel Optane DC Persistent Memory data in a stack buffer, allowing an overlong value to overwrite adjacent memory. Exploitation requires high local privileges and interaction with the preboot environment; impacts can include firmware-level service interruption, arbitrary code execution, or information disclosure.

CVSS severity6.1
Medium
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack-based buffer overflow in Dell PowerEdge BIOS before 2.9.4 allows local users with high privileges to cause denial of service, execute code, or disclose information in the UEFI or BIOS preboot environment. The vulnerable firmware path mishandles Intel Optane DC Persistent Memory data in a stack buffer, allowing an overlong value to overwrite adjacent memory. Exploitation requires high local privileges and interaction with the preboot environment; impacts can include firmware-level service interruption, arbitrary code execution, or information disclosure.

The record

CVE
CVE-2021-21554
Published
Jun 14, 2021
Updated
Sep 16, 2024
Vendor
Dell
Product
PowerEdge BIOS Intel 15G
Classifications
CWE-122, CWE-787
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Jun 14, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 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=unspecified <2.9.4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Dell · PowerEdge BIOS Intel 15Gversion=unspecified <2.9.4

Published CVSS scores

6.7NISTCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
7.2NISTAV:L/AC:L/Au:N/C:C/I:C/A:C
6.1DellCVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:L

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-122Heap-based Buffer Overflow
CWE-787Out-of-bounds Write

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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