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Skype For Business Server CVE-2024-20695

MEDIUM
Improper Access Control (CWE-284)
2024-02-13 secure@microsoft.com
5.7
CVSS 3.1 · Vendor: microsoft
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Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V8 - Authorization Access control enforcement
MITRE ATT&CK

1 technique across 1 tactic: Defense Evasion

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

CVSS score of 5.7 (MEDIUM). Attack characteristics: adjacent network attack vector, low complexity, low privileges required, no user interaction not required.

Exploit ScenarioDerived

Successful exploitation could compromise the medium-severity affected system.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.6% exploitation probability (EPSS)

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AnalysisAI

Skype for Business Information Disclosure Vulnerability. Rated medium severity (CVSS 5.7), this vulnerability is low attack complexity.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified under CWE-284. Affected products include: Microsoft Skype For Business Server.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (microsoft) PRIMARY 5.7 MEDIUM
AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Primary rating from Vendor (microsoft) · only source for this CVE.

CVSS VectorVendor: microsoft

Attack Vector
Adjacent
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

DescriptionCVE.org

Skype for Business Information Disclosure Vulnerability

Threat Intelligence Overview

EPSS Score
0.6%
Top 57% exploitable
Data Quality
3 sources
Confidence: Low

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.6%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Controlled
Automatable· derived
No
Human Impact· derived
Medium

Priority Score

29
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +28
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

Affected Products (CPE)CVE.org

cpe:2.3:a:microsoft:skype_for_business_server:2019:cumulative_update_7:*:*:*:*:*:*
CVE-2026-66302 CRITICAL
9.8 Sep 08

Remote code execution in Microsoft Skype for Business Server (2015 CU13, 2019 CU8, and Subscription Edition CU1) lets an

CVE-2023-41763 MEDIUM POC
5.3 Oct 10

Skype for Business Elevation of Privilege Vulnerability. Rated medium severity (CVSS 5.3), this vulnerability is remotel

CVE-2026-69646 HIGH
8.3 Sep 08

Skype for Business Server's failure to properly verify cryptographic signatures (CWE-347) enables unauthenticated attack

CVE-2026-66304 HIGH
7.5 Sep 08

Server-side request forgery in Microsoft Skype for Business Server exposes internal network resources to unauthenticated

CVE-2026-66307 HIGH
7.5 Sep 08

Unauthenticated network denial-of-service in Microsoft Skype for Business Server allows a remote attacker to crash the s

CVE-2023-36789 HIGH
7.2 Oct 10

Skype for Business Remote Code Execution Vulnerability. Rated high severity (CVSS 7.2), this vulnerability is remotely e

CVE-2023-36786 HIGH
7.2 Oct 10

Skype for Business Remote Code Execution Vulnerability. Rated high severity (CVSS 7.2), this vulnerability is remotely e

CVE-2023-36780 HIGH
7.2 Oct 10

Skype for Business Remote Code Execution Vulnerability. Rated high severity (CVSS 7.2), this vulnerability is remotely e

CVE-2021-26422 HIGH
7.2 May 11

Skype for Business and Lync Remote Code Execution Vulnerability. Rated high severity (CVSS 7.2), this vulnerability is r

CVE-2026-66305 HIGH
7.1 Sep 08

Client-side authentication bypass in Microsoft Skype for Business Server enables a low-privileged network attacker to pe

CVE-2015-2531 MEDIUM
4.3 Sep 09

Cross-site scripting (XSS) vulnerability in the jQuery engine in Microsoft Lync Server 2013 and Skype for Business Serve

CVE-2026-66303 MEDIUM
6.5 Sep 08

Null pointer dereference in Microsoft Skype for Business Server allows any authenticated low-privilege user to crash the

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