CVE-2021-28216

Local firmware compromise via unlocked NVRAM pointer

Published Aug 5, 2021 · Updated Nov 3, 2025

Invalid pointer handling in TianoCore EDK II Master allows local users to compromise firmware via a crafted NVRAM variable. The FPDT code trusts BootPerformanceTablePointer from the firmware performance NVRAM variable and leaves that address variable writable until ReadyToBoot. Low-privileged local access is required; changing the pointer redirects privileged early-boot memory access, enabling memory disclosure, modification, or a crash.

CVSS severity7.8
High
EPSS probability0.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Invalid pointer handling in TianoCore EDK II Master allows local users to compromise firmware via a crafted NVRAM variable. The FPDT code trusts BootPerformanceTablePointer from the firmware performance NVRAM variable and leaves that address variable writable until ReadyToBoot. Low-privileged local access is required; changing the pointer redirects privileged early-boot memory access, enabling memory disclosure, modification, or a crash.

The record

CVE
CVE-2021-28216
Published
Aug 5, 2021
Updated
Nov 3, 2025
Vendor
TianoCore
Product
EDK II
Classifications
CWE-763, CWE-587, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 5, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 3, 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=EDK II Master

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

TianoCore · EDK IIversion=EDK II Master

Published CVSS scores

4.6NVDAV:L/AC:L/Au:N/C:P/I:P/A:P
7.8NVDCVSS:3.1/AV:L/AC:L/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-763Release of Invalid Pointer or Reference
CWE-587Assignment of a Fixed Address to a Pointer
T1068Exploitation for Privilege Escalation

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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