CVE-2025-29828: Windows Schannel Remote Code Execution Vulnerability

Severity: high (CVSS 8.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-06-10 · updated 2026-06-17
Weakness: CWE-401

Description

Missing release of memory after effective lifetime in Windows Cryptographic Services allows an unauthorized attacker to execute code over a network.

Affected products

Microsoft Windows 11: before 10.0.22621.5472 — fixed in 10.0.22621.5472
Microsoft Windows 11: before 10.0.22631.5472 — fixed in 10.0.22631.5472
Microsoft Windows 11: before 10.0.26100.4270 — fixed in 10.0.26100.4270
Microsoft Windows Server 2022: before 10.0.20348.3745 — fixed in 10.0.20348.3745
Microsoft Windows Server 2022, 23H2 Edition (Server Core installation): before 10.0.25398.1665 — fixed in 10.0.25398.1665
Microsoft Windows Server 2025: before 10.0.26100.4270 — fixed in 10.0.26100.4270
Microsoft Windows 11: from 10.0.22621.0 before 10.0.22621.5472 — fixed in 10.0.22621.5472
Microsoft Windows 11 version 22H3: from 10.0.22631.0 before 10.0.22631.5472 — fixed in 10.0.22631.5472
Microsoft Windows 11: from 10.0.22631.0 before 10.0.22631.5472 — fixed in 10.0.22631.5472
Microsoft Windows 11: from 10.0.26100.0 before 10.0.26100.4349 — fixed in 10.0.26100.4349
Microsoft Windows Server 2022: from 10.0.20348.0 before 10.0.20348.3807 — fixed in 10.0.20348.3807
Microsoft Windows Server 2022, 23H2 Edition (Server Core installation): from 10.0.25398.0 before 10.0.25398.1665 — fixed in 10.0.25398.1665
Microsoft Windows Server 2025: from 10.0.26100.0 before 10.0.26100.4349 — fixed in 10.0.26100.4349

How to fix

Upgrade to a fixed version: Microsoft Windows 11 10.0.22621.5472; Microsoft Windows 11 10.0.22631.5472; Microsoft Windows 11 10.0.26100.4270; Microsoft Windows Server 2022 10.0.20348.3745; Microsoft Windows Server 2022, 23H2 Edition (Server Core installation) 10.0.25398.1665; Microsoft Windows Server 2025 10.0.26100.4270; Microsoft Windows 11 10.0.22621.5472; Microsoft Windows 11 version 22H3 10.0.22631.5472; Microsoft Windows 11 10.0.22631.5472; Microsoft Windows 11 10.0.26100.4349; Microsoft Windows Server 2022 10.0.20348.3807; Microsoft Windows Server 2022, 23H2 Edition (Server Core installation) 10.0.25398.1665. Check the vendor advisory for mitigations.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-29828

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