How severe is CVE-2021-43907?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Is CVE-2021-43907 known to be exploited?

4 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Microsoft Visual Studio Code Wsl Extension

CVE-2021-43907

Visual Studio Code WSL Extension Remote Code Execution Vulnerability

Published 2021-12-15 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.038 (89.6th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 90th percentile — 89.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.038 · newest: 0.038 · change: 0.000

Affected products

Microsoft Visual Studio Code Wsl Extension — versions 0
Microsoft Windows Subsystem For Linux

Public proof-of-concept exploits

References

portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43907 (Patch, Vendor Advisory)

Frequently asked questions

What is CVE-2021-43907?: CVE-2021-43907 is a critical-severity vulnerability in Microsoft Visual Studio Code Wsl Extension. CVSS score: 9.8/10. Published 2021-12-15.
How severe is CVE-2021-43907?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2021-43907 known to be exploited?: 4 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.