How severe is CVE-2021-27182?

CVE-2021-27182 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-27182 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (72nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-27182?

CVE-2021-27182 affects Altn Mdaemon. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-27182?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-27182 published?

CVE-2021-27182 was published on 2021-04-14 and last updated on 2026-06-17.

CVE-2021-27182

CVE-2021-27182 is a high-severity vulnerability in Altn Mdaemon with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-74.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 6.5
EPSS exploit prediction: 2% (72nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-74
Affected product: Altn Mdaemon
Published: 2021-04-14
Last modified: 2026-06-17

Description

An issue was discovered in MDaemon before 20.0.4. There is an IFRAME injection vulnerability in Webmail (aka WorldClient). It can be exploited via an email message. It allows an attacker to perform any action with the privileges of the attacked user.

Frequently asked questions

What is CVE-2021-27182?: An issue was discovered in MDaemon before 20.0.4. There is an IFRAME injection vulnerability in Webmail (aka WorldClient). It can be exploited via an email message. It allows an attacker to perform any action with the privileges of the attacked user.
How severe is CVE-2021-27182?: CVE-2021-27182 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-27182 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (72nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-27182?: CVE-2021-27182 affects Altn Mdaemon. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-27182?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-27182 published?: CVE-2021-27182 was published on 2021-04-14 and last updated on 2026-06-17.

References

Affected products (1)

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

More vulnerabilities in Altn Mdaemon

CVE-2021-27181 — High (CVSS 8.8): An issue was discovered in MDaemon before 20.0.4. Remote Administration allows an attacker to perform a fixation of the…
CVE-2021-27183 — High (CVSS 7.2): An issue was discovered in MDaemon before 20.0.4. Administrators can use Remote Administration to exploit an Arbitrary…
CVE-2008-1358 — Medium (CVSS 6.5): Stack-based buffer overflow in the IMAP server in Alt-N Technologies MDaemon 9.6.4 allows remote authenticated users to…
CVE-2021-27180 — Medium (CVSS 6.1): An issue was discovered in MDaemon before 20.0.4. There is Reflected XSS in Webmail (aka WorldClient). It can be…
CVE-2019-8984 — Medium (CVSS 6.1): MDaemon Webmail 14.x through 18.x before 18.5.2 has XSS (issue 2 of 2).
CVE-2019-8983 — Medium (CVSS 6.1): MDaemon Webmail 14.x through 18.x before 18.5.2 has XSS (issue 1 of 2).

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