CVE-2023-4779

User Submitted Posts – Enable Users to Submit Posts from the Front End <= 20230811 - Authenticated (Contributor+) Stored Cross-Site Scripting via Shortcode

2023-09-05 00:00
Ngô Thiên An (ancorn_)

Strategic Overview

Status
Patched in 20230901
Affected Plugin
User Submitted Posts – Enable Users to Submit Posts from the Front End
Affected Version
<= 20230811
CVSS
6.4Medium
Weakness type
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE
CVE-2023-4779
View all User Submitted Posts – Enable Users to Submit Posts from the Front End vulnerabilities

At a glance

CVE-2023-4779 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the User Submitted Posts WordPress plugin, affecting versions <= 20230811. It carries a CVSS score of 6.4 (reachable over the network; low attack complexity). Exploitation requires an authenticated account at Contributor level or above. The issue is fixed in version 20230901; sites on affected versions should update now. Disclosed September 2023, reported by Ngô Thiên An (ancorn_).

Vulnerability Overview

The User Submitted Posts plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's [usp_gallery] shortcode in versions up to, and including, 20230811 due to insufficient input sanitization and output escaping on user supplied attributes like 'before'. This makes it possible for authenticated attackers with contributor-level and above permissions to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

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 interaction from a victim user.

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

User Submitted Posts <= 20230811 carries this weakness at before, and reaching it takes an account at Contributor 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 User Submitted Posts the fix is 20230901: builds <= 20230811 are affected, anything from 20230901 onward is not.

Remediation

Update to version 20230901, or a newer patched version

How does WordSec protect against this?

An attacker needs Contributor 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: User Submitted Posts 20230901 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2023-4779https://www.wordfence.com/threat-intel/vulnerabilities/id/d21ca709-183f-4dd1-849c-f1b2a4f7ec43https://nvd.nist.gov/vuln/detail/CVE-2023-4779

Related records

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