What is CVE-2023-21720?

CVE-2023-21720 is a medium-severity vulnerability in Microsoft Edge Chromium, classified under Buffer Over-read. CVSS score: 5.3/10. Published 2023-02-14.

How severe is CVE-2023-21720?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Vulnerability in Microsoft Edge Chromium

CVE-2023-21720

Microsoft Edge (Chromium-based) Tampering Vulnerability

Published 2023-02-14 · last modified 2026-08-19.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.012 (67.5th percentile), scored 2026-10-01.

Low probability of exploitation in the next 30 days, but still tracked. 68th percentile — 67.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.012 · newest: 0.012 · change: 0.000

Affected products

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

Weakness classification (CWE)

CWE-126 — Buffer Over-read

References

msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21720 (vendor-advisory, Patch, patch, Vendor Advisory)
af854a3a-2127-422b-91ae-364da2661108 (Third Party Advisory)

Frequently asked questions

What is CVE-2023-21720?: CVE-2023-21720 is a medium-severity vulnerability in Microsoft Edge Chromium, classified under Buffer Over-read. CVSS score: 5.3/10. Published 2023-02-14.
How severe is CVE-2023-21720?: Medium severity. CVSS v3 base score is 5.3 out of 10.