CVE-2020-36172

Advanced Custom Fields <= 5.8.11 - Cross-Site Scripting

2020-06-10 00:00

Strategic Overview

Status: Patched in 5.8.12
Affected Plugin: Advanced Custom Fields (ACF®)
Affected Version: < 5.8.12
CVSS: 6.1Medium
Weakness type: CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE: CVE-2020-36172

View all Advanced Custom Fields (ACF®) vulnerabilities

At a glance

CVE-2020-36172 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 < 5.8.12. It carries a CVSS score of 6.1 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 5.8.12; sites on affected versions should update now. Disclosed June 2020.

Vulnerability Overview

The Advanced Custom Fields plugin before 5.8.12 for WordPress mishandles the escaping of strings in Select2 dropdowns, potentially leading to XSS.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site.

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

Reaching this weakness in Advanced Custom Fields (ACF®) < 5.8.12 takes a caller who can reach the endpoint. 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 5.8.12: builds < 5.8.12 are affected, anything from 5.8.12 onward is not.

Remediation

Update to version 5.8.12, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Advanced Custom Fields (ACF®): WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Advanced Custom Fields (ACF®) 5.8.12 closes this, and updating the plugin is the step that ends it.

Firewall
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2020-36172 https://www.wordfence.com/threat-intel/vulnerabilities/id/70110d50-853d-4972-a5a0-b5c566ba7de6 https://nvd.nist.gov/vuln/detail/CVE-2020-36172

Related records

Same weakness class

Other vulnerabilities in Advanced Custom Fields (ACF®)

CVSS Vector

6.1

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

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionRequired
ScopeChanged
ConfidentialityLow
IntegrityLow
AvailabilityNone

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