CVE-2021-24180

Related Posts for WordPress <= 2.0.3 - Reflected Cross-Site Scripting

2021-03-15 00:00

Strategic Overview

Status: Patched in 2.0.4
Affected Plugin: Related Posts for WordPress
Affected Version: <= 2.0.3
CVSS: 5.4Medium
Weakness type: CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE: CVE-2021-24180

At a glance

CVE-2021-24180 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the Related Posts for WordPress WordPress plugin, affecting versions <= 2.0.3. It carries a CVSS score of 5.4 (reachable over the network; low attack complexity). The issue is fixed in version 2.0.4; sites on affected versions should update now. Disclosed March 2021, reported by Nguyen Anh Tien.

Vulnerability Overview

Unvalidated input and lack of output encoding within the Related Posts for WordPress plugin before 2.0.4 lead to a Reflected Cross-Site Scripting (XSS) vulnerability within the 'lang' GET parameter while editing a post, triggered when users with the capability of editing posts access a malicious URL.

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')

Related Posts for WordPress <= 2.0.3 carries this weakness at lang, and reaching it 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 Related Posts for WordPress the fix is 2.0.4: builds <= 2.0.3 are affected, anything from 2.0.4 onward is not.

Remediation

Update to version 2.0.4, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Related Posts for WordPress: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Related Posts for WordPress 2.0.4 closes this, and updating the plugin is the step that ends it.

Firewall
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2021-24180 https://www.wordfence.com/threat-intel/vulnerabilities/id/1a5d9290-b480-45f7-9ac7-a20475b805e8 https://nvd.nist.gov/vuln/detail/CVE-2021-24180

Related records

Same weakness class

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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