Executive Summary

CVE-2026-5638 is a path traversal vulnerability in the HerikLyma CPPWebFramework up to version 3.1. The framework improperly concatenates user-supplied URLs with the web root path without sanitizing sequences like "../", which allows attackers to traverse directories outside the intended web root.

This vulnerability enables remote attackers to read arbitrary files on the host system that have certain whitelisted file extensions, such as .ini, .txt, .xml, .json, .zip, .php, .html, .rar, .doc, .pdf, .mp3, and .mp4, without authentication.

An example exploit involves sending a crafted HTTP GET request with a path traversal payload (e.g., GET /../../../../home/Test.txt) to retrieve files outside the web root, including sensitive configuration files like CPPWeb.ini.

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Impact Analysis

This vulnerability allows remote attackers to read arbitrary files on the server without authentication by exploiting path traversal. This can lead to unauthorized disclosure of sensitive information, such as configuration files and other data stored on the host.

Such unauthorized file access can compromise the confidentiality of the system, potentially exposing secrets, credentials, or other sensitive data that could be leveraged for further attacks.

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Detection Guidance

This vulnerability can be detected by attempting to exploit the path traversal flaw through crafted HTTP GET requests that include directory traversal sequences (e.g., "../") to access files outside the web root.

For example, sending a request like GET /../../../../home/Test.txt to the affected server can reveal if arbitrary files can be read without authentication.

A practical detection method is to use tools like curl or wget to send such crafted requests and observe if the server returns the contents of files outside the intended directory.

• curl -v "http://target-server/../../../../home/Test.txt"
• wget --server-response "http://target-server/../../../../home/Test.txt"

Additionally, a Python proof-of-concept script exists that sends specially crafted GET requests bypassing URL normalization to confirm the vulnerability.

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Mitigation Strategies

Immediate mitigation steps include restricting or disabling access to the vulnerable CPPWebFramework instance until a patch or official fix is available.

Since the vulnerability allows unauthenticated remote file reads via path traversal, it is critical to implement input validation and sanitization to prevent directory traversal sequences in URLs.

As a temporary measure, consider deploying web application firewalls (WAFs) or intrusion detection systems (IDS) to block requests containing suspicious path traversal patterns such as "../".

Monitor logs for unusual access patterns attempting to read sensitive files like CPPWeb.ini or other configuration files.

If possible, isolate the affected service in a restricted network segment to limit exposure.

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Compliance Impact

The vulnerability allows unauthenticated remote attackers to perform path traversal and read arbitrary files on the host system, including sensitive configuration files such as CPPWeb.ini.

This unauthorized access to sensitive files could lead to exposure of personal or confidential data, which may violate data protection requirements under regulations like GDPR or HIPAA.

Therefore, exploitation of this vulnerability could compromise compliance with standards that mandate protection of sensitive information and secure access controls.

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