What is CVE-2021-42308?

CVE-2021-42308 is a low-severity vulnerability in Microsoft Edge Chromium, classified under Authentication Bypass by Spoofing. CVSS score: 3.1/10. Published 2021-11-24.

How severe is CVE-2021-42308?

Low severity. CVSS v3 base score is 3.1 out of 10.

Vulnerability in Microsoft Edge Chromium

CVE-2021-42308

Microsoft Edge (Chromium-based) Spoofing Vulnerability

Published 2021-11-24 · last modified 2026-08-19.

CVSS v3 metric

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

EPSS exploit prediction

EPSS: 0.013 (69.9th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 70th percentile — 69.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.013 · newest: 0.013 · change: +0.001

Affected products

Microsoft Edge Chromium
Microsoft Edge (Chromium-Based) — versions 1.0.0

Weakness classification (CWE)

CWE-290 — Authentication Bypass by Spoofing

References

af854a3a-2127-422b-91ae-364da2661108 (Patch, Vendor Advisory)
msrc.microsoft.com/update-guide/vulnerability/CVE-2021-42308 (vendor-advisory, patch)

Frequently asked questions

What is CVE-2021-42308?: CVE-2021-42308 is a low-severity vulnerability in Microsoft Edge Chromium, classified under Authentication Bypass by Spoofing. CVSS score: 3.1/10. Published 2021-11-24.
How severe is CVE-2021-42308?: Low severity. CVSS v3 base score is 3.1 out of 10.