What is the CVSS score of CVE-2021-27183?

CVE-2021-27183 has a CVSS 3.1 base score of 7.2 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 2.7%.

Is there a public PoC exploit available for CVE-2021-27183?

Yes, a public proof-of-concept exploit is available for CVE-2021-27183. Prioritise patching immediately. EPSS: 2.7%.

Mdaemon CVE-2021-27183

HIGH

Externally Controlled Reference to a Resource in Another Sphere (CWE-610)

2021-04-14 cve@mitre.org

RCE Mdaemon Altn

7.2

CVSS 3.1 · NVD

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Vulnerability Assessment

Weakness	CWE CWE-610 OWASP Top 10:2025 A05:2025 - Injection ASVS 5.0 V4 - API and Web Service External resource reference control
Impact	CVSS score of 7.2 (HIGH). Attack characteristics: network attack vector, low complexity, high privileges required, no user interaction not required. Public proof-of-concept exploit code is available.
Exploit ScenarioDerived	This vulnerability can be exploited remotely over the network. Successful exploitation could compromise the high-severity affected system.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).

No patch listed yet 2.7% exploitation probability (EPSS)

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AnalysisAI

An issue was discovered in MDaemon before 20.0.4. Rated high severity (CVSS 7.2), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

Affects your stack

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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-610. An issue was discovered in MDaemon before 20.0.4. Administrators can use Remote Administration to exploit an Arbitrary File Write vulnerability. An attacker is able to create new files in any location of the filesystem, or he may be able to modify existing files. This vulnerability may directly lead to Remote Code Execution. Affected products include: Altn Mdaemon. Version information: before 20.0.4..

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 7.2 HIGH

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

High

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

DescriptionNVD

An issue was discovered in MDaemon before 20.0.4. Administrators can use Remote Administration to exploit an Arbitrary File Write vulnerability. An attacker is able to create new files in any location of the filesystem, or he may be able to modify existing files. This vulnerability may directly lead to Remote Code Execution.

Threat Intelligence Overview

EPSS Score

2.7%

Top 16% exploitable

Exploit

POC

Public exploit code exists

Data Quality

3 sources

Confidence: Low

NVD

CVE.org

EPSS

GitHub

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 HIGH

CISA KEV No

Public POC Yes

EPSS 2.7%

Patch available No

Active threat No

Deciding rule

HIGH severity (CVSS 7.0-8.9)

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

Poc

System Exposure· derived

Open

Automatable· derived

Human Impact· derived

Medium

Priority Score

Low Medium High Critical

KEV: 0

EPSS: +3

CVSS: +36

PoC: +20

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Remote Code Execution CRITICAL

Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.

Affected Products (CPE)NVD

cpe:2.3:a:altn:mdaemon:*:*:*:*:*:*:*:*

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References

Advisories & patches

ADVISORY https://www.altn.com/Support/SecurityUpdate/MD011221_MDaemon_EN/

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GitHub PoC

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