SB2026090938 - Multiple vulnerabilities in Microsoft Skype for Business

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Main Vulnerability Database SB2026090938

SB2026090938 - Multiple vulnerabilities in Microsoft Skype for Business

Published: September 9, 2026

Security Bulletin ID SB2026090938
CSH Severity
High
Patch available
YES
Number of vulnerabilities 7
Exploitation vector Remote access
Highest impact Code execution

Breakdown by Severity

High 14% Medium 57% Low 29%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 7 vulnerabilities.


1) Improper Verification of Cryptographic Signature (CVE-ID: CVE-2026-69646)

CWE-ID: CWE-347 - Improper Verification of Cryptographic Signature

CVSSv4: 8.7 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to compromise the target system.

The vulnerability exists due to improper verification of cryptographic signature in Skype for Business. A remote attacker on the local network can perform spoofing attack.


2) Cross-site scripting (CVE-ID: CVE-2026-69642)

CWE-ID: CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVSSv4: 5.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N]


The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.

The vulnerability exists due to insufficient sanitization of user-supplied data in Skype for Business. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in context of vulnerable website.

Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.


3) Information Exposure Through an Error Message (CVE-ID: CVE-2026-66306)

CWE-ID: CWE-209 - Information Exposure Through an Error Message

CVSSv4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to gain access to potentially sensitive information.

The vulnerability exists due to generation of error message containing sensitive information in Skype for Business. A remote attacker can gain unauthorized access to sensitive information on the system.


4) Use of Client-Side Authentication (CVE-ID: CVE-2026-66305)

CWE-ID: CWE-603 - Use of Client-Side Authentication

CVSSv4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to compromise the target system.

The vulnerability exists due to use of client-side authentication in Skype for Business. A remote user can perform spoofing attack.


5) Server-Side Request Forgery (SSRF) (CVE-ID: CVE-2026-66304)

CWE-ID: CWE-918 - Server-Side Request Forgery (SSRF)

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]


The disclosed vulnerability allows a remote attacker to perform SSRF attacks.

The vulnerability exists due to insufficient validation of user-supplied input in Skype for Business. A remote attacker can send a specially crafted HTTP request and trick the application to initiate requests to arbitrary systems.

Successful exploitation of this vulnerability may allow a remote attacker gain access to sensitive data, located in the local network or send malicious requests to other servers from the vulnerable system.


6) External Control of File Name or Path (CVE-ID: CVE-2026-66302)

CWE-ID: CWE-73 - External Control of File Name or Path

CVSSv4: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to execute arbitrary code on the system.

The vulnerability exists due to external control of file name or path in Skype for Business. A remote attacker can execute arbitrary code on the target system.


7) Cross-site scripting (CVE-ID: CVE-2026-63523)

CWE-ID: CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVSSv4: 5.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N]


The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.

The vulnerability exists due to insufficient sanitization of user-supplied data in Skype for Business. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in context of vulnerable website.

Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.


Remediation

Install update from vendor's website.

References