CVE-2026-1781 (GCVE-0-2026-1781)
Vulnerability from cvelistv5
Published
2026-03-11 01:22
Modified
2026-04-08 16:35
Severity ?
VLAI Severity ?
EPSS score ?
CWE
- CWE-862 - Missing Authorization
Summary
The MC4WP: Mailchimp for WordPress plugin for WordPress is vulnerable to Missing Authorization in all versions up to, and including, 4.11.1. This is due to the plugin trusting the `_mc4wp_action` POST parameter without validation, allowing unauthenticated attackers to force the form to process unsubscribe actions instead of subscribe actions. This makes it possible for unauthenticated attackers to arbitrarily unsubscribe any email address from the connected Mailchimp audience via the `_mc4wp_action` parameter, granted they can obtain the form ID (which is publicly exposed in the HTML source).
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| dvankooten | MC4WP: Mailchimp for WordPress |
Version: 0 ≤ 4.11.1 |
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"id": "CVE-2026-1781",
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"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
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}
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{
"url": "https://plugins.trac.wordpress.org/browser/mailchimp-for-wp/tags/4.11.1/includes/forms/class-form-listener.php#L53"
},
{
"url": "https://plugins.trac.wordpress.org/browser/mailchimp-for-wp/tags/4.11.1/includes/forms/class-form-listener.php#L207"
},
{
"url": "https://plugins.trac.wordpress.org/browser/mailchimp-for-wp/tags/4.11.1/includes/forms/class-form.php#L461"
},
{
"url": "https://cwe.mitre.org/data/definitions/862.html"
},
{
"url": "https://github.com/ibericode/mailchimp-for-wordpress/commit/5fdebc2a5e22d11287d011697a6b09331bd96fa5"
},
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"url": "https://plugins.trac.wordpress.org/changeset?sfp_email=\u0026sfph_mail=\u0026reponame=\u0026new=3477825%40mailchimp-for-wp%2Ftrunk\u0026old=3443118%40mailchimp-for-wp%2Ftrunk\u0026sfp_email=\u0026sfph_mail="
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"state": "PUBLISHED"
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"vulnerability-lookup:meta": {
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"dataType": "CVE_RECORD",
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}
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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