CVE-2025-40629 Overview
CVE-2025-40629 is a path traversal vulnerability [CWE-22] affecting PNETLab 4.2.10, a network emulation platform used by network engineers and security professionals. The application fails to properly sanitize user-supplied input within its file access mechanisms. Attackers can manipulate file path parameters in HTTP requests to read sensitive files located outside the intended directory.
The flaw is exploitable remotely without authentication or user interaction. Successful exploitation results in unauthorized disclosure of confidential files stored on the host system, including configuration data and credentials.
Critical Impact
Unauthenticated remote attackers can traverse the file system and read arbitrary files from the PNETLab host, exposing sensitive configuration and credential data.
Affected Products
- PNETLab 4.2.10
Discovery Timeline
- 2025-05-16 - CVE-2025-40629 published to the National Vulnerability Database (NVD)
- 2026-04-15 - Last updated in NVD database
Technical Details for CVE-2025-40629
Vulnerability Analysis
The vulnerability resides in PNETLab 4.2.10's file access handlers, which accept user-controlled path components within HTTP requests. The application does not validate or canonicalize these path components before resolving them on the file system. Attackers can inject directory traversal sequences such as ../ to escape the intended document root.
The issue is classified under [CWE-22] Improper Limitation of a Pathname to a Restricted Directory. The Exploit Prediction Scoring System places this issue in a higher exploitation likelihood tier compared to typical disclosed CVEs.
Exploitation requires only network access to the PNETLab web interface. No credentials, configuration changes, or user interaction are required.
Root Cause
The root cause is missing input sanitization in HTTP request handlers responsible for serving files. The application concatenates user-supplied path values directly into file system operations without filtering traversal sequences or enforcing a base directory boundary. Canonical path validation is absent.
Attack Vector
An attacker sends crafted HTTP requests to PNETLab endpoints that accept file path parameters. By inserting traversal sequences in the file path argument, the attacker forces the application to resolve paths outside the intended directory. The server returns the contents of files such as /etc/passwd, application configuration files, or database credentials.
The vulnerability mechanism is documented in the INCIBE CERT Notice: Path Traversal Vulnerability. No verified proof-of-concept code is included in this article; refer to the advisory for technical reproduction details.
Detection Methods for CVE-2025-40629
Indicators of Compromise
- HTTP requests to PNETLab containing directory traversal sequences such as ../, ..%2f, or encoded variants in URL parameters or path segments.
- Web server access logs showing successful responses (HTTP 200) to requests referencing sensitive system files including /etc/passwd, /etc/shadow, or PNETLab configuration files.
- Unusual outbound transfers of file contents from the PNETLab host following anomalous inbound HTTP requests.
Detection Strategies
- Inspect web server and reverse proxy logs for path parameters containing traversal characters or URL-encoded equivalents targeting PNETLab endpoints.
- Deploy web application firewall (WAF) rules that flag and block HTTP requests containing directory traversal patterns against the PNETLab service.
- Correlate file access events on the PNETLab host with corresponding HTTP requests to identify reads of files outside the application's working directory.
Monitoring Recommendations
- Enable verbose HTTP access logging on the PNETLab server and forward logs to a centralized SIEM for path traversal pattern matching.
- Monitor file integrity and access events on system directories that should never be reached by the PNETLab process.
- Alert on repeated 200-OK responses to requests containing unusual path components, which may indicate enumeration activity.
How to Mitigate CVE-2025-40629
Immediate Actions Required
- Restrict network access to the PNETLab management interface using firewall rules or VPN-only access until a vendor patch is verified and applied.
- Review web server logs for prior exploitation attempts dating back to the affected version's deployment.
- Rotate any credentials, API keys, or certificates stored on the PNETLab host that may have been exposed through arbitrary file reads.
Patch Information
At the time of publication, no vendor patch reference is listed in the NVD entry for CVE-2025-40629. Administrators should consult the INCIBE CERT Notice: Path Traversal Vulnerability for the latest remediation guidance and monitor the PNETLab project for an updated release beyond version 4.2.10.
Workarounds
- Place PNETLab behind a reverse proxy configured to reject HTTP requests containing ../, ..\, or URL-encoded traversal sequences in path parameters.
- Apply WAF signatures for [CWE-22] path traversal and enable strict input validation rules for all PNETLab request paths and query parameters.
- Run the PNETLab service under a least-privilege account with file system access constrained to the application directory using mandatory access controls such as AppArmor or SELinux.
- Isolate PNETLab on a dedicated network segment with no access to credential stores or sensitive infrastructure.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
