CVE-2025-67487 in Static Web Server
Summary
by MITRE • 12/09/2025
Static Web Server (SWS) is a production-ready web server suitable for static web files or assets. Versions 2.40.0 and below contain symbolic links (symlinks) which can be used to access files or directories outside the intended web root folder. SWS generally does not prevent symlinks from escaping the web server’s root directory. Therefore, if a malicious actor gains access to the web server’s root directory, they could create symlinks to access other files outside the designated web root folder either by URL or via the directory listing. This issue is fixed in version 2.40.1.
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Analysis
by VulDB Data Team • 12/12/2025
The vulnerability described in CVE-2025-67487 affects Static Web Server (SWS) version 2.40.0 and earlier, representing a critical path traversal flaw that undermines the fundamental security boundary of web server configurations. This issue stems from the server's failure to properly validate symbolic links within its file system hierarchy, allowing attackers to bypass intended access controls. The vulnerability specifically targets the web root directory protection mechanism, which is a core security feature designed to isolate web-accessible content from sensitive system files. When symlinks are present within the web root, they can point to directories or files outside the intended serving scope, creating an unauthorized access vector that directly violates the principle of least privilege and secure configuration practices.
The technical implementation of this vulnerability exploits the inherent trust placed in the web server's directory structure while failing to implement proper symlink resolution checks. Attackers can leverage this flaw by creating malicious symbolic links within the web root directory that point to sensitive files such as configuration files, system binaries, or other restricted resources. The vulnerability manifests when the web server processes these symlinks without validating their target paths against the designated web root boundaries, effectively allowing path traversal attacks to succeed. This flaw operates at the file system level and can be exploited through multiple vectors including direct URL access and directory listing enumeration, making it particularly dangerous as it provides multiple attack surfaces for exploitation. The issue is classified under CWE-22 Path Traversal and aligns with ATT&CK technique T1083 File and Directory Discovery, demonstrating how attackers can leverage server misconfigurations to expand their reconnaissance capabilities.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can enable more sophisticated attacks including privilege escalation, data exfiltration, and system compromise. When combined with other vulnerabilities or attack vectors, this flaw can serve as a stepping stone for attackers to gain deeper access to the underlying system. The vulnerability affects any deployment where the web server root directory is writable by untrusted users, which is common in shared hosting environments or applications where administrative privileges are not properly restricted. Organizations using affected versions of SWS should immediately consider the implications for their security posture, as the vulnerability can be exploited without requiring elevated privileges or specialized tools beyond basic file system manipulation capabilities. The fix implemented in version 2.40.1 addresses this by introducing proper symlink validation that ensures all symbolic links are resolved within the intended web root boundaries, thereby preventing unauthorized access to system resources.
Mitigation strategies should focus on immediate deployment of the patched version 2.40.1 while implementing additional security controls to prevent similar vulnerabilities in other components. Organizations should conduct comprehensive audits of their web server configurations to identify and remove any existing symlinks that could potentially be exploited, particularly those pointing to system directories or sensitive files. The implementation of proper access controls and file system permissions can help prevent unauthorized symlink creation, while regular security assessments should include verification of web server root directory integrity. This vulnerability highlights the importance of validating all file system operations within web server contexts and demonstrates how seemingly simple configuration issues can create significant security risks. Security teams should also consider implementing automated monitoring for unauthorized file system changes and establish incident response procedures specifically addressing path traversal vulnerabilities in web server environments. The remediation process should include thorough testing to ensure that the patch does not introduce compatibility issues with existing web applications while maintaining the security improvements necessary to protect against this specific attack vector.