CVE-2021-38576

A BIOS bug in firmware for a particular PC model leaves the Platform authorization value empty. This can be used to permanently brick the TPM in multiple ways, as well as to non-permanently DoS the system.

Published: 2022-01-03 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-38576 is rated Moderate Risk (53.1/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.18%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-38576

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.26% 1.18% +0.92%
2 2026-02-01 0.21% 0.26% +0.04%
3 2025-07-16 — 0.21% —

Full EPSS history (12 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-38576

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
7.8 2.0 HIGH
AV:N/AC:L/Au:N/C:N/I:N/A:C Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:C)
Complete availability impact.
 10.0 6.9 [email protected]

Weakness enumeration for CVE-2021-38576

OS Trackers for CVE-2021-38576

vendor priority summary link
debian not yet assigned CVE-2021-38576 not yet assigned priority: Debian including 1 source packages (edk2), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-38576
ubuntu low CVE-2021-38576 low priority: Ubuntu including 1 source packages (edk2), 15 status rows across 15 suites (bionic, focal, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 8, ignored 3, needed 2, needs-triage 2. https://ubuntu.com/security/CVE-2021-38576

Affected software / configurations for CVE-2021-38576

Vendor Product Version Raw CPE
tianocore edk2 201808 cpe:2.3:a:tianocore:edk2:201808:*:*:*:*:*:*:*
tianocore edk2 201811 cpe:2.3:a:tianocore:edk2:201811:*:*:*:*:*:*:*
tianocore edk2 201903 cpe:2.3:a:tianocore:edk2:201903:*:*:*:*:*:*:*
tianocore edk2 201905 cpe:2.3:a:tianocore:edk2:201905:*:*:*:*:*:*:*
tianocore edk2 201908 cpe:2.3:a:tianocore:edk2:201908:*:*:*:*:*:*:*
tianocore edk2 201911 cpe:2.3:a:tianocore:edk2:201911:*:*:*:*:*:*:*
tianocore edk2 202002 cpe:2.3:a:tianocore:edk2:202002:*:*:*:*:*:*:*
tianocore edk2 202005 cpe:2.3:a:tianocore:edk2:202005:*:*:*:*:*:*:*
tianocore edk2 202008 cpe:2.3:a:tianocore:edk2:202008:*:*:*:*:*:*:*
tianocore edk2 202011 cpe:2.3:a:tianocore:edk2:202011:*:*:*:*:*:*:*
tianocore edk2 202102 cpe:2.3:a:tianocore:edk2:202102:*:*:*:*:*:*:*
tianocore edk2 202105 cpe:2.3:a:tianocore:edk2:202105:*:*:*:*:*:*:*

References for CVE-2021-38576

cvelogic Threat Intelligence