CVE-2026-85818

Analyzed Analyzed - Analysis Complete

Improper Cryptographic Signature Verification in Windows Schannel

Publication date: 2026-10-13

Last updated on: 2026-10-16

Assigner: Microsoft Corporation

Description

Improper verification of cryptographic signature in Windows Schannel allows an unauthorized attacker to perform spoofing over a network.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-10-13

Last Modified

2026-10-16

Generated

2026-10-19

AI Q&A

2026-10-14

EPSS Evaluated

2026-10-18

NVD

CVE-2026-85818

EUVD

EUVD-2026-99528

Affected Vendors & Products

Vendor	Product	Version / Range
microsoft	windows_11_23h2	to 10.0.22631.7652 (exc)
microsoft	windows_11_23h2	to 10.0.22631.7652 (exc)
microsoft	windows_11_24h2	to 10.0.26100.9711 (exc)
microsoft	windows_11_24h2	to 10.0.26100.9711 (exc)
microsoft	windows_11_25h2	to 10.0.26200.9711 (exc)
microsoft	windows_11_25h2	to 10.0.26200.9711 (exc)
microsoft	windows_11_26h1	to 10.0.28000.3231 (exc)
microsoft	windows_11_26h1	to 10.0.28000.3231 (exc)
microsoft	windows_11_26h2	to 10.0.26300.9711 (exc)
microsoft	windows_11_26h2	to 10.0.26300.9711 (exc)
microsoft	windows_server_2025	to 10.0.26100.33650 (exc)
microsoft	windows_server_2022	to 10.0.20348.5761 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-347	The product does not verify, or incorrectly verifies, the cryptographic signature for data.

Attack-Flow Graph

Executive Summary

This vulnerability involves improper verification of cryptographic signatures in Windows Schannel, a component handling secure communications. An unauthorized attacker can exploit this to perform spoofing attacks over a network, potentially impersonating legitimate systems or users.

Impact Analysis

This vulnerability could allow attackers to intercept, modify, or redirect network traffic by impersonating trusted systems. It may lead to unauthorized access to sensitive data, man-in-the-middle attacks, or bypassing security controls.

Mitigation Strategies

Apply the latest security updates from Microsoft to address the improper cryptographic signature verification in Windows Schannel. Monitor Microsoft's update guide for patches and install them promptly.

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