CVE-2025-12276

Executive Summary

CVE-2025-12276 is an information disclosure vulnerability in the LearnHouse platform (up to commit 98dfad76aad70711a8113f6c1fdabfccf10509ca). The flaw resides in the Image Handler component, allowing an unauthenticated remote attacker to access sensitive information. The exploit is publicly available, and the vendor has not responded to disclosure attempts. The product uses a rolling release model, making version tracking difficult. No patch or official fix exists at this time.

Supply Chain & Package Security

LearnHouse is a self-hosted learning management system. The vulnerability is in the application’s own image handling code, not in a third-party package. However, because the vendor is unresponsive, users must rely on manual mitigation or forking the repository. No NPM, PyPI, Go, or Ruby package is directly affected.

CVSS Breakdown & Threat Level

• CVSS Score: 4.3 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: Low
• Integrity Impact: None
• Availability Impact: None

The low EPSS score (0.0%) suggests limited active exploitation, but the public exploit increases risk.

Deep Dive & Mechanics

The vulnerability is in the Image Handler component of LearnHouse. The handler does not properly validate or sanitize image file paths or metadata, allowing an attacker to request arbitrary files from the server. By manipulating image parameters (e.g., path traversal or direct file read), an attacker can retrieve sensitive files such as configuration files, database credentials, or user data.

The rolling release model means the exact vulnerable version is unknown, but any deployment before the commit 98dfad76aad70711a8113f6c1fdabfccf10509ca is affected.

Vulnerable vs. Patched Code

No patched code is available. The vulnerable code likely resembles:

# Vulnerable example (pseudocode)
def serve_image(request):
    path = request.GET.get('path')
    # No validation
    return open(path, 'rb').read()

A patched version would include:

# Patched example (pseudocode)
import os
ALLOWED_DIR = '/var/www/learnhouse/images/'

def serve_image(request):
    path = request.GET.get('path')
    full_path = os.path.normpath(os.path.join(ALLOWED_DIR, path))
    if not full_path.startswith(ALLOWED_DIR):
        return "Forbidden", 403
    return open(full_path, 'rb').read()

Exploitation & Lab Setup

Red Team

1. Setup: Deploy a vulnerable LearnHouse instance (commit before 98dfad76).
2. Exploit: Use a simple HTTP request to traverse directories:

   curl "http://target/upload?path=../../../etc/passwd"
   

3. Extract: Retrieve sensitive files like .env, config.php, or database dumps.

Blue Team

1. Detection: Monitor for unusual file path requests (e.g., ../, %2e%2e/).
2. Mitigation: Implement a Web Application Firewall (WAF) rule to block path traversal patterns.
3. Harden: Restrict web server permissions and disable directory listing.

Indicators of Compromise (IOCs)

• Network: HTTP requests containing ../ or %2e%2e in image handler endpoints.
• File: Unauthorized access to /etc/passwd, .env, or config.php.
• Logs: Web server logs showing 200 responses to path traversal attempts.

Detection Engineering

YARA Rule

rule CVE_2025_12276_ImageHandler {
    meta:
        description = "Detects path traversal attempts in LearnHouse image handler"
        author = "Valters IT"
        date = "2025-04-10"
    strings:
        $path_traversal = /\.\.\// nocase
        $encoded_traversal = /%2e%2e%2f/ nocase
    condition:
        any of them
}

Sigma Rule

title: LearnHouse Image Handler Path Traversal
id: 8a4b3c2d-1e5f-4a7b-9c8d-0e1f2a3b4c5d
status: experimental
description: Detects path traversal attempts targeting LearnHouse image handler
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'GET'
        cs-uri-stem|contains: '/upload'
        cs-uri-query|contains: 
            - '..'
            - '%2e%2e'
    condition: selection
falsepositives:
    - Legitimate use of dots in filenames
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-12276 LearnHouse Image Handler Path Traversal"; flow:to_server,established; content:"GET"; http_method; content:"/upload"; http_uri; content:"../"; http_uri; sid:1000001; rev:1;)

Remediation & Mitigation

• Immediate: Block path traversal patterns in WAF or reverse proxy.
• Short-term: Fork the LearnHouse repository and apply input validation to the image handler.
• Long-term: Monitor for vendor response or switch to an alternative LMS.
• No patch available – rely on compensating controls.

Valters IT
DevSecOps & Cyber Threat Intelligence