Vulnerability in Microsoft Windows 11 Version 23h2
CVE-2026-103577
Insecure default variable initialization in Microsoft QUIC allows an unauthorized attacker to bypass a security feature over a network.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:H.
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)
References
- Microsoft QUIC Security Feature Bypass Vulnerability (vendor-advisory, patch)
Frequently asked questions
- What is CVE-2026-103577?
- CVE-2026-103577 is a high-severity vulnerability in Microsoft Windows 11 Version 23h2, classified under CWE-453. CVSS score: 7.5/10. Published 2026-10-13.
- How severe is CVE-2026-103577?
- High severity. CVSS v3 base score is 7.5 out of 10.