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CVE-2026-120534: Advanced Custom Fields: Extended PRO Unrestricted File Upload Vulnerability

CVE-2026-120534 explained: critical Unrestricted File Upload in Advanced Custom Fields: Extended PRO. CVSS 9.8. Affected versions, detection, fixes and CTEM priority

Last updated: Nov 3, 2026

CVSS
9.8 CRITICAL
EPSS
n/a
CISA KEV
Not listed
CWE
CWE-434

Sources: National Vulnerability Database, CVE.org, CISA KEV, FIRST EPSS

CVE-2026-120534 Overview

The Advanced Custom Fields: Extended PRO plugin for WordPress is vulnerable to Limited Code Injection in all versions up to, and including, 0.9.2.6 via the render_field function. This is due to insufficient validation of form configuration parameters before merging into field settings and passing to call_user_func_array in the render_field method. This makes it possible for unauthenticated attackers to call arbitrary WordPress functions with controlled arguments. Method 1 requires the administrator to enable the non-default 'shortcode_preview' setting for the target form, while Method 2 requires the server environment to lack OpenSSL functions, causing ACF Pro's acf_decrypt to fall back to unverified base64 decoding.

Critical Impact

Remote, unauthenticated attackers can exploit this Unrestricted File Upload in Advanced Custom Fields: Extended PRO. The CVSS base score is 9.8 (Critical).

Affected Products

  • Advanced Custom Fields: Extended PRO: see the vendor advisory for the exact affected versions

Discovery Timeline

  • 2026-11-03: CVE-2026-120534 published to the National Vulnerability Database by security@wordfence.com
  • 2026-11-03: last updated in the NVD database

Technical Details for CVE-2026-120534

Vulnerability Analysis

CVE-2026-120534 is a Unrestricted File Upload weakness (CWE-434: Unrestricted File Upload) in Advanced Custom Fields: Extended PRO. Based on its CVSS vector, the flaw can be reached over the network, needs no login, and needs no user interaction. Dangerous file types, such as scripts, can be uploaded and run.

With a CVSS base score of 9.8, apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Root Cause

The weakness is classified as CWE-434: Unrestricted File Upload. Dangerous file types, such as scripts, can be uploaded and run.

Attack Vector

Based on the CVSS vector, the flaw can be reached over the network, needs no login, and needs no user interaction. Attack complexity is low complexity.

No exploitation in the wild is confirmed by CISA at the time of the last update. Check the references below for any vendor or researcher proof of concept.

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

Detection Methods for CVE-2026-120534

Detection Strategies

  • Inventory every instance of Advanced Custom Fields: Extended PRO and compare the running version with the affected range above.
  • Check external attack surface scans for internet facing instances of the component.
  • Run an authenticated vulnerability scan once your scanner ships a check for this CVE.

Monitoring Recommendations

  • Forward Advanced Custom Fields: Extended PRO application, access and audit logs to your SIEM for retrospective hunting.
  • Alert on new processes, configuration changes or outbound connections from the affected service.
  • Track the vendor advisory and the CISA KEV catalog for changes in exploitation status.

How to Mitigate CVE-2026-120534

Immediate Actions Required

  • Apply the fixed version of Advanced Custom Fields: Extended PRO named in the vendor advisory.
  • Prioritize internet facing and business critical instances first.
  • Rescan after the change to confirm the exposure is closed.

Patch Information

Use the fixed version listed in the vendor advisory for Advanced Custom Fields: Extended PRO.

Workarounds

  • If patching must wait, restrict network access to the affected service and place it behind authentication or a web application firewall rule.

CWE References

Technical References

This entry is built directly from NVD, CISA KEV and EPSS data. Verify fixed versions in the vendor advisory before you deploy.

Frequently asked questions

CVE-2026-120534 is a critical severity Unrestricted File Upload in Advanced Custom Fields: Extended PRO with a CVSS score of 9.8. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

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