dbcve.org
Missing AuthorizationWeakness · CWE-862

CVE-2026-56063

HIGH · 8.3 CVSS v3.1 Published 2026-06-26
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
92/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click 8 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Unauthenticated Broken Access Control in MailChimp Block <= 1.1.15 versions.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

Unauthenticated broken access control vulnerability in MailChimp Block WordPress plugin versions 1.1.15 and below allows attackers to access restricted functionality without any authentication credentials, likely due to missing capability checks or nonce validation on sensitive operations.

MitigationUpdate MailChimp Block plugin to the latest version immediately. If no patched version is available, disable the plugin until a fix is released, as the unauthenticated nature of this vulnerability poses immediate risk.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check MailChimp Block plugin version
    Log into WordPress admin, navigate to Plugins > Installed Plugins, find MailChimp Block, and read the version number displayed under the plugin name. Alternatively, access the server and open the main plugin file (usually wp-content/plugins/mailchimp-block/mailchimp-block.php) and look for the Version header in the plugin comment block.
    Affected if The displayed version is 1.1.15 or any version lower than 1.1.15.
  2. Confirm plugin is active
    In WordPress admin under Plugins > Installed Plugins, verify that MailChimp Block shows as 'Active' rather than 'Inactive'. If accessing the server directly, check the wp_options table for the option named active_plugins to see if mailchimp-block is listed.
    Affected if The plugin is active and the version is 1.1.15 or below.
  3. Inspect plugin for sensitive AJAX or admin actions
    Access the plugin directory on the server and review PHP files for AJAX handlers (wp_ajax_ hooks) or admin action hooks. Look for functions that perform sensitive operations such as saving settings, managing subscribers, or modifying data without calling current_user_can() or checking nonce tokens.
    Affected if Sensitive functions exist that lack capability checks (current_user_can) or nonce validation, and the plugin version is 1.1.15 or below.
  4. Test unauthenticated access to plugin endpoints
    If you have permission and are conducting authorized testing, send HTTP requests to common plugin endpoints (such as /wp-admin/admin-ajax.php?action=mailchimp_block_*) without providing authentication cookies or a logged-in session. Alternatively, review server access logs for requests to plugin URLs originating from unauthenticated IP addresses.
    Affected if Requests to sensitive plugin actions complete successfully without requiring authentication, indicating the broken access control is present.

A user is affected if the MailChimp Block plugin is installed, active, and running version 1.1.15 or lower, with unauthenticated access to sensitive functionality possible due to missing capability checks or nonce validation.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update MailChimp Block plugin to the latest version immediately. If no patched version is available, disable the plugin until a fix is released, as the unauthenticated nature of this vulnerability poses immediate risk.

Recommended fix Moderate confidence

1.1.16 or latest available version

  1. Check current plugin version in WordPress dashboard under Plugins > Installed Plugins
  2. Update MailChimp Block plugin to version 1.1.16 or later
  3. Verify the update was successful by confirming the new version number

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
13.0 hours of engineering $2,290
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-56063 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data