CVE-2026-103577

Insecure default variable initialization in Microsoft QUIC allows an unauthorized attacker to bypass a security feature over a network.

Score

CVSS 3.1 7.5 High

Status

Analyzed - secure@microsoft.com

Published

2026-10-13

Last modified

2026-10-28

Weaknesses

CWE-453

Affected products

• Windows 11 23H2 (Microsoft)
• Windows 11 23h2 (Microsoft)
• Windows 11 24H2 (Microsoft)
• Windows 11 24h2 (Microsoft)
• Windows 11 25H2 (Microsoft)
• Windows 11 25h2 (Microsoft)
• Windows 11 26H1 (Microsoft)
• Windows 11 26h1 (Microsoft)
• Windows 11 26h2 (Microsoft)
• Windows 11 Version 26h2 For Arm64-based Systems (Microsoft)
• Windows Server 2022 (Microsoft)
• Windows Server 2025 (Microsoft)

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-103577