What is CVE-2026-83906?

CVE-2026-83906 is a medium-severity vulnerability in Microsoft Windows 11 Version 23h2, classified under Incorrect Implementation of Authentication Algorithm. CVSS score: 6.5/10. Published 2026-10-13.

How severe is CVE-2026-83906?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in Microsoft Windows 11 Version 23h2

CVE-2026-83906

Incorrect implementation of authentication algorithm in Windows Shell allows an unauthorized attacker to perform spoofing over a network.

Published 2026-10-13 · last modified 2026-10-13.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Weakness classification (CWE)

CWE-303 — Incorrect Implementation of Authentication Algorithm

References

Windows Shell Spoofing Vulnerability (vendor-advisory, patch)

Frequently asked questions

What is CVE-2026-83906?: CVE-2026-83906 is a medium-severity vulnerability in Microsoft Windows 11 Version 23h2, classified under Incorrect Implementation of Authentication Algorithm. CVSS score: 6.5/10. Published 2026-10-13.
How severe is CVE-2026-83906?: Medium severity. CVSS v3 base score is 6.5 out of 10.