CyberSecBulletin
CVE-2026-120534NVD status: Deferred

Advanced Custom Fields: Extended PRO: Unrestricted Upload of File with Dangerous Type

Published Updated By the CyberSecBulletin desk

CVE-2026-120534 is a critical-severity unrestricted upload of file with dangerous type vulnerability in Advanced Custom Fields: Extended PRO from ACF Extended, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Advanced Custom Fields: Extended PRO versions: 0.9.2.6 and earlier. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.31% chance of exploitation within 30 days, which is low compared with other CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Check which version of Advanced Custom Fields: Extended PRO you run against the affected versions below, and install the vendor's latest release.
  2. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
ACF ExtendedAdvanced Custom Fields: Extended PRO0.9.2.6 and earlierNot stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (wordfence.com).

Official description

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.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Unrestricted Upload of File with Dangerous Type

The product allows the upload or transfer of dangerous file types that are automatically processed within its environment.

How developers prevent this class of flaw

  • Generate a new, unique filename for an uploaded file instead of using the user-supplied filename, so that no external input is used at all.
  • When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs.
  • Consider storing the uploaded files outside of the web document root entirely. Then, use other mechanisms to deliver the files dynamically.

More Unrestricted Upload of File with Dangerous Type vulnerabilities (CWE-434)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).

References

Patches and release notes

Recent Unrestricted Upload of File with Dangerous Type vulnerabilities

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