CVE-2021-27182Public exploitNetwork attack vector

User-privileged actions via email-borne IFRAME injection

Published Apr 14, 2021 · Updated Aug 3, 2024

IFRAME injection in MDaemon WorldClient before 20.0.4 allows remote authenticated users to act with a webmail user's privileges via email. WorldClient renders an attacker-supplied IFRAME from an email message without neutralizing the element before displaying the message. Exploitation requires the recipient to open the crafted message, and resulting actions are limited to those available to that webmail account.

CVSS severity8.8
High
EPSS probability1.55%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

IFRAME injection in MDaemon WorldClient before 20.0.4 allows remote authenticated users to act with a webmail user's privileges via email. WorldClient renders an attacker-supplied IFRAME from an email message without neutralizing the element before displaying the message. Exploitation requires the recipient to open the crafted message, and resulting actions are limited to those available to that webmail account.

The record

CVE
CVE-2021-27182
Published
Apr 14, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-74, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 14, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
6.5NIST NVDAV:N/AC:L/Au:S/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo