CVE-2019-11871

Custom Field Suite <= 2.5.14 - Authenticated Cross-Site Scripting

2019-05-08 00:00

Strategic Overview

Status: Patched in 2.5.15
Affected Plugin: Custom Field Suite
Affected Version: <= 2.5.14
CVSS: 5.4Medium
Weakness type: CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE: CVE-2019-11871

View all Custom Field Suite vulnerabilities

At a glance

CVE-2019-11871 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the Custom Field Suite WordPress plugin, affecting versions <= 2.5.14. It carries a CVSS score of 5.4 (reachable over the network; low attack complexity). Exploitation requires an authenticated account. The issue is fixed in version 2.5.15; sites on affected versions should update now. Disclosed May 2019, reported by reddy.io.

Vulnerability Overview

The Custom Field Suite plugin before 2.5.15 for WordPress has XSS for editors or admins.

Technical Analysis

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

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

Reaching this weakness in Custom Field Suite <= 2.5.14 takes any authenticated account. 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 Custom Field Suite the fix is 2.5.15: builds <= 2.5.14 are affected, anything from 2.5.15 onward is not.

Remediation

Update to version 2.5.15, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Custom Field Suite: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Custom Field Suite 2.5.15 closes this, and updating the plugin is the step that ends it.

Firewall
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2019-11871 https://www.wordfence.com/threat-intel/vulnerabilities/id/0e4fec06-13d3-49ce-afe5-8dca15cf1f0a https://nvd.nist.gov/vuln/detail/CVE-2019-11871

Related records

Same weakness class

Other vulnerabilities in Custom Field Suite

CVSS Vector

5.4

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

Base

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

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