CVE-2026-4431 — The Easy Post Submission plugin for WordPress is vulnerable to unauthorized modification…¶
Key facts
CVE-2026-4431 is a Critical (9.1) vulnerability: The Easy Post Submission plugin for WordPress is vulnerable to unauthorized modification…. This entry ships a detection-only PoC and a Docker test lab.
| CVE | CVE-2026-4431 |
| Severity | Critical (9.1) |
| Detection / prevention | — |
| PoC | poc.py |
| Source | 2026/CVE-2026-4431/ |
Details¶
English | 한국어
Description¶
The Easy Post Submission plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the create_post() function in all versions up to, and including, 2.3.0. This is due to the rbsm_submit_post AJAX action being registered for unauthenticated users via wp_ajax_nopriv_rbsm_submit_post without any authorization checks when a postId parameter is supplied. This makes it possible for unauthenticated attackers to modify the title, content, excerpt, categories, and tags of arbitrary posts, as well as change the post status to draft (effectively unpublishing them) via the 'postId' parameter.
Vulnerability Details¶
| Property | Value |
|---|---|
| CVE ID | CVE-2026-4431 |
| CVSS Score | 9.1 |
Proof of Concept¶
Download¶
# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2026/CVE-2026-4431/poc.py
Usage¶
# Run PoC against target
python3 poc.py --target <TARGET_URL>
# With authentication
python3 poc.py --target <TARGET_URL> --username <USER> --password <PASS>
⚠️ Warning: This PoC is for authorized security testing only. It uses detection-only techniques and does not exploit or damage target systems.
Test Lab¶
This repository includes a Docker-based test environment with both vulnerable and patched applications.
Quick Start¶
# Clone and navigate to CVE directory
cd CVE-2026-4431
# Start both applications
docker-compose up -d
# Run tests
./run-tests.sh # Linux/Mac
./run-tests.ps1 # Windows PowerShell
Application Endpoints¶
| Application | URL | Status |
|---|---|---|
| Vulnerable App | http://localhost:8080 | Shows vulnerability |
| Patched App | http://localhost:8081 | Demonstrates fix |
Directory Structure¶
├── README.md # English documentation
├── README_KO.md # Korean documentation
├── poc.py # PoC detection script
├── docker-compose.yml # Container orchestration
├── run-tests.sh # Linux/Mac test runner
├── run-tests.ps1 # Windows test runner
├── vulnerable-app/ # Vulnerable version
│ ├── app.py
│ ├── Dockerfile
│ └── requirements.txt
└── patched-app/ # Fixed version
├── app.py
├── Dockerfile
└── requirements.txt
References¶
- https://plugins.trac.wordpress.org/browser/easy-post-submission/tags/2.2.0/includes/client-ajax-handler.php#L1157
- https://plugins.trac.wordpress.org/browser/easy-post-submission/tags/2.2.0/includes/client-ajax-handler.php#L38
- https://plugins.trac.wordpress.org/browser/easy-post-submission/tags/2.2.0/includes/client-ajax-handler.php#L974
- https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&new=3488045%40easy-post-submission%2Ftrunk&old=3427523%40easy-post-submission%2Ftrunk
- https://www.wordfence.com/threat-intel/vulnerabilities/id/15494ccf-7c9d-4566-9e80-2da94172a3dd?source=cve
Generated by PoC Generator on 2026-08-10T06:40:22.489252341
Frequently asked questions¶
What is CVE-2026-4431?¶
CVE-2026-4431 is a Critical (9.1) vulnerability: The Easy Post Submission plugin for WordPress is vulnerable to unauthorized modification…. This entry ships a detection-only PoC and a Docker test lab.
How do I detect CVE-2026-4431?¶
Run the detection-only PoC included with this entry against your Docker test lab to confirm whether a target is affected; pair it with your own IDS logging.
How do I block or mitigate CVE-2026-4431?¶
Upgrade to a fixed version per the vendor advisory; the NVD record lists the affected versions. Use the included PoC to verify your remediation.
For authorized security testing and research only. See the full source and NVD record.