What is the CVSS score of CVE-2021-24073?

CVE-2021-24073 has a CVSS 3.1 base score of 6.5 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:L/A:N. EPSS exploitation probability: 1.6%.

Is there a patch available for CVE-2021-24073?

Yes, a patch is available for CVE-2021-24073. Update the affected software to the latest version immediately.

Lync Server CVE-2021-24073

MEDIUM

2021-02-25 secure@microsoft.com

Information Disclosure Microsoft Lync Server Skype For Business Server

6.5

CVSS 3.1 · Vendor: microsoft

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Vulnerability Assessment

Impact	CVSS score of 6.5 (MEDIUM). Attack characteristics: network attack vector, high complexity, low privileges required, user interaction required.
Exploit ScenarioDerived	This vulnerability can be exploited remotely over the network. 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 1.6% exploitation probability (EPSS)

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AnalysisAI

Skype for Business and Lync Spoofing Vulnerability. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable.

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

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Technical ContextAI · show details

Affected products include: Microsoft Lync Server, 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 6.5 MEDIUM

AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:L/A:N

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

CVSS VectorVendor: microsoft

Attack Vector

Network

Attack Complexity

High

Privileges Required

Low

User Interaction

Required

Scope

Changed

Confidentiality

High

Integrity

Low

Availability

None

DescriptionCVE.org

Skype for Business and Lync Spoofing Vulnerability

Threat Intelligence Overview

EPSS Score

1.6%

Top 27% exploitable

Data Quality

2 sources

Confidence: Low

NVD

CVE.org

EPSS

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 1.6%

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

Open

Automatable· derived

Human Impact· derived

Medium

Priority Score

Low Medium High Critical

KEV: 0

EPSS: +2

CVSS: +32

PoC: 0

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Information Disclosure MEDIUM

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:lync_server:2013:*:*:*:*:*:*:*

cpe:2.3:a:microsoft:skype_for_business_server:2015:cu8:*:*:*:*:*:*

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References

Advisories & patches

PATCH https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-24073

Search Externally

GitHub PoC

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