CVE-2021-44223

Name: CVE-2021-44223
Creator: NVD / NIST
Published: 2021-11-25T15:15:09.8+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 28.98%

Last modified Jun 17, 2026

CVE-2021-44223 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. WordPress before 5.8 lacks support for the Update URI plugin header. This makes it easier for remote attackers to execute arbitrary code via a supply-chain attack against WordPress installations that use any plugin for which the slug satisfies the naming constraints of the WordPress.org Plugin Directory but is not yet present in that directory.. EPSS estimates a 28.98% chance of exploitation in the next 30 days.

Description

WordPress before 5.8 lacks support for the Update URI plugin header. This makes it easier for remote attackers to execute arbitrary code via a supply-chain attack against WordPress installations that use any plugin for which the slug satisfies the naming constraints of the WordPress.org Plugin Directory but is not yet present in that directory.

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

28.98%

97.9th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Vendor	Product	Versions
Wordpress	Wordpress	< 5.8

References

https://make.wordpress.org/core/2021/06/29/introducing-update-uri-plugin-header-in-wordpress-5-8/Release Notes, Vendor Advisory
https://vavkamil.cz/2021/11/25/wordpress-plugin-confusion-update-can-get-you-pwned/Exploit, Third Party Advisory
https://make.wordpress.org/core/2021/06/29/introducing-update-uri-plugin-header-in-wordpress-5-8/Release Notes, Vendor Advisory
https://vavkamil.cz/2021/11/25/wordpress-plugin-confusion-update-can-get-you-pwned/Exploit, Third Party Advisory

Timeline

Published: Nov 25, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-44223?

How severe is CVE-2021-44223?

CVE-2021-44223 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 28.98% probability of exploitation in the next 30 days.

How do I fix CVE-2021-44223?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-44223?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST