CVE-2026-69646

Undergoing Analysis Undergoing Analysis - In Progress

Improper Cryptographic Signature Verification in Skype for Business Allows Spoofing

Publication date: 2026-09-08

Last updated on: 2026-09-09

Assigner: Microsoft Corporation

Description

Improper verification of cryptographic signature in Skype for Business allows an unauthorized attacker to perform spoofing over an adjacent network.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-09-08

Last Modified

2026-09-09

Generated

2026-09-29

AI Q&A

2026-09-10

EPSS Evaluated

2026-09-27

NVD

CVE-2026-69646

Affected Vendors & Products

Vendor	Product	Version / Range
microsoft	skype_for_business	*

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 Skype for Business. An unauthorized attacker can exploit this to perform spoofing attacks over an adjacent network, potentially impersonating legitimate users or systems.

Impact Analysis

An attacker could impersonate a trusted user or system in your network, leading to unauthorized access, data breaches, or misinformation. This may disrupt communications and compromise sensitive information shared via Skype for Business.

Compliance Impact

This vulnerability could lead to unauthorized access or data breaches, violating confidentiality requirements in GDPR and HIPAA. Organizations may face legal penalties, reputational damage, and loss of compliance certifications if exploited.

Mitigation Strategies

Apply the latest security updates from Microsoft for Skype for Business as soon as they become available to address the improper cryptographic signature verification issue.

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