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TI-2026-85767 Aliases CVE-2026-118166GHSA-7vpp-4gxp-3rx5

MC4WP Mailchimp for WordPress: Unauthenticated Shortcode Execution

Priority LOW 21CWE-74Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
High
Impact type
—
Confidentiality · integrity · availability
Low · Low · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA.

Summary

The MC4WP: Mailchimp for WordPress plugin before 4.15.0 does not stop request-derived values in its dynamic content tags from being processed as shortcodes when a form is embedded with the block. Unauthenticated visitors can run any registered shortcode with attacker-chosen attributes. Exploitation requires the site owner to have added a request-derived tag to the form content and to embed the form with the block instead of the classic shortcode. The weakness is classified as CWE-74, and CVSS 3.1 scores it 4.8 (MEDIUM).

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Description from the CNA

The MC4WP: Mailchimp for WordPress WordPress plugin before 4.15.0 does not prevent request-derived values in its dynamic content tags from being processed as shortcodes when a form is embedded with its block, allowing unauthenticated visitors to execute arbitrary registered shortcodes with attacker-chosen attributes. This requires the site owner to have added a request-derived tag to the form content and to embed the form with the block rather than the classic shortcode.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00177 7th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by the CNA
Fix Fixed MC4WP: Mailchimp for WordPress (Unknown): 4.15.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
UnknownMC4WP: Mailchimp for WordPressbefore 4.15.04.15.0Patch availableCNA
  • MC4WP: Mailchimp for WordPress VendorUnknown Affected before 4.15.0 Fixed in 4.15.0 Patch available CNA

Remediation

Update MC4WP: Mailchimp for WordPress to version 4.15.0 or later.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

  • Fix · CNA MC4WP: Mailchimp for WordPress (Unknown) Fixed in 4.15.0

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    MC4WP: Mailchimp for WordPress 4.15.0

    2 records Highest priority Priority LOW 2 LOW

    Other records, highest priority first

    • TI-2026-85749 Incorrect authorization in MC4WP Mailchimp for WordPress pluginPriority LOW 29
    Show all 2 records →

Timeline

  1. 2026-11-06 Threatist record created from CVE-2026-118166
  2. 2026-11-06 Alias added: GHSA-7vpp-4gxp-3rx5
  3. 2026-11-06 Weakness changed · CISA ADP
  4. 2026-11-06 CISA SSVC decision points changed

References

Exploit 1

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences