CVE-2021-20866

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.8% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-12-13 · updated 2026-06-17
Weakness: CWE-862

Description

Advanced Custom Fields versions prior to 5.11 and Advanced Custom Fields Pro versions prior to 5.11 contain a missing authorization vulnerability in obtaining the user list which may allow a user to obtain the unauthorized information via unspecified vectors.

Affected products

WP Engine Advanced Custom Fields: before 5.11 — fixed in 5.11

How to fix

Upgrade to a fixed version: WP Engine Advanced Custom Fields 5.11. Check the vendor advisory for mitigations.

References

https://jvn.jp/en/jp/JVN09136401/index.html
https://wordpress.org/plugins/advanced-custom-fields/
https://www.advancedcustomfields.com/
https://jvn.jp/en/jp/JVN09136401/index.html
https://wordpress.org/plugins/advanced-custom-fields/
https://www.advancedcustomfields.com/

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