CVE-2021-38578 [High] | Security Vulnerability in Edk2

CVE-2021-38578 is rated Moderate Risk (50.6/100): CVSS High severity, with medium exploitation likelihood (EPSS 0.98%). Review affected assets and schedule remediation.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.06%	0.98%	+0.92%
2	2025-11-21	0.24%	0.06%	-0.18%
3	2025-11-18	—	0.24%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.06%

0.98%

+0.92%

2025-11-21

0.24%

0.06%

-0.18%

2025-11-18

—

0.24%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
7.4	3.1	HIGH	`CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:L` Click to expand Attack vector (AV:L) They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by. Attack complexity (AC:H) Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work. Privileges required (PR:H) They need powerful rights—admin, root, or similar—before this pays off. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:C) Breaking this can reach past the original component and bite other resources—bigger blast radius. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:L) Might cause slowdowns, glitches, or partial disruption—not a full brick.	0.8	6.0	[email protected]
9.8	3.1	CRITICAL	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	3.9	5.9	[email protected]
7.5	2.0	HIGH	`AV:N/AC:L/Au:N/C:P/I:P/A:P` 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:P) Partial confidentiality impact. Integrity impact (I:P) Partial integrity impact. Availability impact (A:P) Partial availability impact.	10.0	6.4	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

7.4

3.1

HIGH

CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:L Click to expand

Attack vector (AV:L): They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:H): Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:H): They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C): Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:H): They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:L): Might cause slowdowns, glitches, or partial disruption—not a full brick.

0.8

6.0

[email protected]

9.8

3.1

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:H): They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

3.9

5.9

[email protected]

7.5

2.0

HIGH

AV:N/AC:L/Au:N/C:P/I:P/A:P 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:P): Partial confidentiality impact.
Integrity impact (I:P): Partial integrity impact.
Availability impact (A:P): Partial availability impact.

10.0

6.4

[email protected]

OS Trackers for CVE-2021-38578

vendor	priority	summary	link
`alpine`	high	CVE-2021-38578: 1 source package rows (edk2); 9 state rows across 6 repos (3.17-community, 3.18-community, 3.19-community, 3.20-community, 3.22-community, edge-community); fixed 0, open 9.	https://security.alpinelinux.org/vuln/CVE-2021-38578
`debian`	not yet assigned	CVE-2021-38578 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-2021-38578
`redhat`	medium	—	https://access.redhat.com/security/cve/CVE-2021-38578
`suse`	high	CVE-2021-38578 severity important: SUSE including 57 source package names (edk2-ovmf-20221207gitfff6d81270b5-9.el9_2, edk2-tools-20221207gitfff6d81270b5-9.el9_2, …), 150 product×package rows across 45 product lines (SUSE CaaS Platform 4.0, SUSE Enterprise Storage 7, … (45 product lines)): Fixed 146, Known Not Affected 4.	https://www.suse.com/security/cve/CVE-2021-38578/
`ubuntu`	medium	CVE-2021-38578 medium priority: Ubuntu including 1 source packages (edk2), 11 status rows across 11 suites (bionic, focal, impish, jammy, kinetic, lunar, mantic, noble, trusty, upstream, xenial): released 4, ignored 3, not-affected 3, needs-triage 1.	https://ubuntu.com/security/CVE-2021-38578

Affected software / configurations for CVE-2021-38578

Vendor	Product	Version	Raw CPE
tianocore	edk2	<= 202202	cpe:2.3:a:tianocore:edk2::::::::
insyde	kernel	5.0	cpe:2.3:o:insyde:kernel:5.0:::::::*
insyde	kernel	5.1	cpe:2.3:o:insyde:kernel:5.1:::::::*
insyde	kernel	5.2	cpe:2.3:o:insyde:kernel:5.2:::::::*
insyde	kernel	5.3	cpe:2.3:o:insyde:kernel:5.3:::::::*
insyde	kernel	5.4	cpe:2.3:o:insyde:kernel:5.4:::::::*
insyde	kernel	5.5	cpe:2.3:o:insyde:kernel:5.5:::::::*

References for CVE-2021-38578

URL	Tags
https://bugzilla.tianocore.org/show_bug.cgi?id=3387	Issue Tracking Vendor Advisory
https://www.insyde.com/security-pledge/SA-2023024	Third Party Advisory
https://lists.debian.org/debian-lts-announce/2025/06/msg00007.html

URL

CVE-2021-38578

Exploit prediction scoring system (EPSS) score for CVE-2021-38578

Common vulnerability scoring system (CVSS) metrics for CVE-2021-38578

Weakness enumeration for CVE-2021-38578

OS Trackers for CVE-2021-38578

Affected software / configurations for CVE-2021-38578

References for CVE-2021-38578