CVE-2023-40068

Advanced Custom Fields 6.1 - 6.1.7 - Authenticated (Administrator+) Stored Cross-Site Scripting

2023-08-03 00:00
Satoo Nakano

Strategic Overview

Status
Patched in 6.1.8
Affected Plugin
Advanced Custom Fields (ACF®)
Affected Version
6.1 – 6.1.7
CVSS
4.4Medium
Weakness type
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE
CVE-2023-40068
View all Advanced Custom Fields (ACF®) vulnerabilities

At a glance

CVE-2023-40068 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the Advanced Custom Fields (ACF®) WordPress plugin, affecting versions 6.1 – 6.1.7. It carries a CVSS score of 4.4 (reachable over the network). Exploitation requires an authenticated account at Administrator level or above. The issue is fixed in version 6.1.8; sites on affected versions should update now. Disclosed August 2023, reported by Satoo Nakano.

Vulnerability Overview

The Advanced Custom Fields plugin for WordPress is vulnerable to Stored Cross-Site Scripting via ACF post type and taxonomy labels in versions 6.1 to 6.1.7 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with administrator-level permissions and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This only affects multi-site installations and installations where unfiltered_html has been disabled.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, and no interaction from a victim user.

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Reaching this weakness in Advanced Custom Fields (ACF®) 6.1 – 6.1.7 takes an account at Administrator level or above. Cross-site scripting happens when input from a request is written into a page without being escaped for the context it lands in, so the browser parses attacker-supplied text as markup or script.

Injected script runs with the privileges of whoever views the affected page, which is how these flaws turn into administrator session theft, silent account creation or persistent backdoors in page content. For Advanced Custom Fields (ACF®) the fix is 6.1.8: builds 6.1 – 6.1.7 are affected, anything from 6.1.8 onward is not.

Remediation

Update to version 6.1.8, or a newer patched version

How does WordSec protect against this?

An attacker needs Administrator access first, so the firewall sees the attempt as traffic from a logged-in account: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Advanced Custom Fields (ACF®) 6.1.8 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2023-40068https://www.wordfence.com/threat-intel/vulnerabilities/id/f412bdb0-953d-4375-85c2-b87f3aa77d60https://nvd.nist.gov/vuln/detail/CVE-2023-40068

Related records

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