What is the CVSS score of CVE-2021-27180?

CVE-2021-27180 has a CVSS 3.1 base score of 6.1 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N. EPSS exploitation probability: 0.9%.

Is there a public PoC exploit available for CVE-2021-27180?

Yes, a public proof-of-concept exploit is available for CVE-2021-27180. Prioritise patching immediately. EPSS: 0.9%.

Is there a patch available for CVE-2021-27180?

Yes, a patch is available for CVE-2021-27180. Update the affected software to the latest version immediately.

Mdaemon CVE-2021-27180

MEDIUM

Cross-site Scripting (XSS) (CWE-79)

2021-04-14 cve@mitre.org

XSS Mdaemon Altn

6.1

CVSS 3.1 · NVD

View

Vulnerability Assessment

Weakness	CWE CWE-79 OWASP Top 10:2025 A05:2025 - Injection ASVS 5.0 V1 - Encoding and Sanitization Output encoding, context-aware escaping MITRE ATT&CK 2 techniques across 2 tactics: Initial Access, Execution The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Impact	CVSS score of 6.1 (MEDIUM). Attack characteristics: network attack vector, low complexity, no privileges required, user interaction required. Public proof-of-concept exploit code is available.
Exploit ScenarioDerived	A remote attacker could inject malicious scripts into web pages viewed by other users by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).

Patch available 0.9% exploitation probability (EPSS)

Get an e-mail when this CVE is exploited, patched or re-scored. Free account.

Alert me

AnalysisAI

An issue was discovered in MDaemon before 20.0.4. Rated medium severity (CVSS 6.1), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Sanitize all user input, use Content-Security-Policy headers, encode output contextually (HTML, JS, URL). Use frameworks with built-in XSS protection.

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 as Cross-Site Scripting (XSS) (CWE-79), which allows attackers to inject malicious scripts into web pages viewed by other users. An issue was discovered in MDaemon before 20.0.4. There is Reflected XSS in Webmail (aka WorldClient). It can be exploited via a GET request. It allows performing any action with the privileges of the attacked user. Affected products include: Altn Mdaemon. Version information: before 20.0.4..

Know when Mdaemon gets its next vulnerability

Watch products and get an email when something new is published
Check this CVE against your own stack and servers
Exploit and PoC references, threat intelligence from 22 sources

Continue with Google Continue with GitHub

No credit card · 7-day full trial

Severity by source

NVD PRIMARY 6.1 MEDIUM

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

DescriptionNVD

An issue was discovered in MDaemon before 20.0.4. There is Reflected XSS in Webmail (aka WorldClient). It can be exploited via a GET request. It allows performing any action with the privileges of the attacked user.

Threat Intelligence Overview

EPSS Score

0.9%

Top 44% 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 MEDIUM

CISA KEV No

Public POC Yes

EPSS 0.9%

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

Poc

System Exposure· derived

Open

Automatable· derived

Human Impact· derived

Medium

Priority Score

Low Medium High Critical

KEV: 0

EPSS: +1

CVSS: +30

PoC: +20

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Cross-Site Scripting MEDIUM

Cross-Site Scripting occurs when an application accepts untrusted data and sends it to a web browser without proper validation or encoding.

Affected Products (CPE)NVD

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

More in Mdaemon

View all

CVE-2021-27182 HIGH This Week POC

8.8 Apr 14

An issue was discovered in MDaemon before 20.0.4. Rated high severity (CVSS 8.8), this vulnerability is remotely exploit

CVE-2021-27181 HIGH This Week POC

8.8 Apr 14

An issue was discovered in MDaemon before 20.0.4. Rated high severity (CVSS 8.8), this vulnerability is remotely exploit

CVE-2021-27183 HIGH This Week POC

7.2 Apr 14

An issue was discovered in MDaemon before 20.0.4. Rated high severity (CVSS 7.2), this vulnerability is remotely exploit

CVE-2023-52269 MEDIUM This Month POC

4.8 Dec 31

MDaemon SecurityGateway through 9.0.3 allows XSS via a crafted Message Content Filtering rule. Rated medium severity (CV

CVE-2012-2584 MEDIUM This Month POC

4.3 Aug 12

Multiple cross-site scripting (XSS) vulnerabilities in Alt-N MDaemon Free 12.5.4 allow remote attackers to inject arbitr

CVE-2019-8984 MEDIUM This Month

6.1 Feb 21

MDaemon Webmail 14.x through 18.x before 18.5.2 has XSS (issue 2 of 2). Rated medium severity (CVSS 6.1), this vulnerabi

CVE-2019-8983 MEDIUM This Month

6.1 Feb 21

MDaemon Webmail 14.x through 18.x before 18.5.2 has XSS (issue 1 of 2). Rated medium severity (CVSS 6.1), this vulnerabi

CVE-2022-29976 MEDIUM This Month

5.4 May 11

An Authenticated Reflected Cross-site scripting at BCC Parameter was discovered in MDaemon before 22.0.0 . Rated medium

CVE-2022-29975 MEDIUM This Month

5.4 May 11

An Authenticated Reflected Cross-site scripting at CC Parameter was discovered in MDaemon before 22.0.0 . Rated medium s

CVE-2025-3929 MEDIUM This Month

5.3 Apr 29

An XSS issue was discovered in MDaemon Email Server version 25.0.1 and below. Rated medium severity (CVSS 5.3), this vul

CVE-2024-11182 MEDIUM This Month

5.3 Nov 15

An XSS issue was discovered in MDaemon Email Server before version 24.5.1c. Rated medium severity (CVSS 5.3), this vulne

Same weakness CWE-79 – Cross-site Scripting (XSS)

View all

CVE-2020-3580 MEDIUM POC

6.1

CVE-2013-7389 MEDIUM POC

4.3

CVE-2021-25299 MEDIUM POC

6.1

CVE-2014-2120 MEDIUM

6.1

CVE-2023-40000 HIGH POC

8.3

CVE-2016-8581 MEDIUM POC

6.1

CVE-2013-5223 MEDIUM POC

5.4

CVE-2025-52367 MEDIUM POC

5.4

Same technique XSS

View all

CVE-2017-9248 CRITICAL POC

9.8

CVE-2013-1710 CRITICAL POC

10.0

CVE-2024-52875 HIGH POC

8.8

References

Advisories & patches

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

Search Externally

GitHub PoC

Exploit-DB PacketStorm Snyk Rapid7 Nuclei Templates Trickest PoC

Back