CVE-2026-103577

EUVD-2026-100390
Insecure default variable initialization in Microsoft QUIC allows an unauthorized attacker to bypass a security feature over a network.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
7.5 HIGH
NETWORK
HIGH
NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:H
Awaiting analysis
This vulnerability is currently awaiting analysis.
Base Score
CVSS 3.x
EPSS Score
Percentile: 42.65%
Windows Releases
Platform
Version
Windows 11
23H2 (arm64, x64)
KB5126653
24H2 (arm64, x64)
KB5127648
25H2 (arm64, x64)
KB5127648
26H1 (arm64, x64)
KB5127646
26H2 (arm64, x64)
KB5127648
Windows Server 2022
Server Core
KB5126655
Standard
KB5126655
Windows Server 2025
Server Core
KB5126646
Standard
KB5126646
Common Weakness Enumeration
References
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-103577