CVE-2021-43243

FAUCET Score

CVE-2021-43243 is an information disclosure vulnerability affecting Microsoft VP9 Video Extensions. With a CVSS score of 5.5 (Medium), it can be exploited locally with low attack complexity and low privileges, potentially leading to high confidentiality impact. There is no known active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or KEV entry. While community discussion and media coverage are minimal, Microsoft addressed this flaw in their December 2021 Patch Tuesday.

Impacted Technologies

Vendor	Product	Version(s)	CPE
		Range not provided by sourceCPE matchmatch criteria	cpe:2.3:a:microsoft:vp9_video_extensions:-:::::::*

CVSS Data

CVSS version used by this source: 3.1

5.5MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

NONE

Availability Impact

NONE

Exploitability Score

1.8

Impact Score

3.6

CvssVersion

3.1

Exploit Intelligence

EPSS Score

0.77%

Probability of exploitation in next 30 days

EPSS Percentile

51.9%

Percentile rank of EPSS score among Peer Group

As of 2026-07-28

Model: v2026.06.15

This CVE's current EPSS score of 0.0077 is in the 95th percentile among its peer group of 15,940 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.0 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

microsoftpatch availablevia nvd_reference

View patch

Vendor Advisories (1)

microsoft2021-Dec/CVE-2021-43243Important

VP9 Video Extensions Information Disclosure Vulnerability

Dec 14, 2021

References

portal.msrc.microsoft.com / en-US/security-guidance/advisory/CVE-2021-43243

PatchVendor Advisory