CVE-2023-40203Network attack vector

Unauthenticated service interruption requiring user interaction

Published Dec 13, 2024 · Updated Apr 28, 2026

Missing authorization in Mailmunch Forms for Mailchimp 3.1.4 and earlier allows remote attackers to interrupt service via unspecified vectors. The CNA and vendor advisory do not identify the affected function, request, or authorization check that mishandles untrusted input. Exploitation is unauthenticated but requires a logged-in subscriber to perform an action; the published impact is limited to service availability, and the interruption mode is undisclosed.

CVSS severity8.8
High
EPSS probability0.69%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing authorization in Mailmunch Forms for Mailchimp 3.1.4 and earlier allows remote attackers to interrupt service via unspecified vectors. The CNA and vendor advisory do not identify the affected function, request, or authorization check that mishandles untrusted input. Exploitation is unauthenticated but requires a logged-in subscriber to perform an action; the published impact is limited to service availability, and the interruption mode is undisclosed.

The record

CVE
CVE-2023-40203
Published
Dec 13, 2024
Updated
Apr 28, 2026
Vendor
Mailmunch
Product
Mailmunch Forms for Mailchimp
Classifications
CWE-862, CAPEC-180
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 13, 2024CVE publishedPublication date reported by the CVE source.
  2. Apr 28, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=n/a <=3.1.4 changes=[{"at":"3.1.5","status":"unaffected"}]

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mailmunch · Mailmunch Forms for Mailchimpversion=n/a <=3.1.4 changes=[{"at":"3.1.5","status":"unaffected"}]

Published CVSS scores

8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
4.3PatchstackCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-862Missing Authorization
CAPEC-180Exploiting Incorrectly Configured Access Control Security Levels

Public exploit references

No public exploit references are available in this record.

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

Technologies

Your stack

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Your stack

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