CVE-2026-67185 in TinyWeb
Summary
by MITRE • 07/28/2026
TinyWeb through 0.0.8 contains a path traversal vulnerability that allows unauthenticated attackers to read arbitrary files by submitting ../ sequences in the URL path, which are concatenated directly to the configured web root in HttpBuilder::buildResponse() without normalization, dot-segment removal, or boundary checks. Attackers can craft a single request with ../ sequences that pass through the URL parser unchanged and reach the filesystem call via HttpFile::setFile(), exposing sensitive files such as credential stores and private keys when the server process runs as root.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 07/28/2026
This vulnerability exists within TinyWeb versions 0.0.8 and earlier, representing a critical path traversal flaw that enables unauthenticated remote attackers to access arbitrary files on the target system. The weakness stems from improper input validation within the HttpBuilder::buildResponse() method where URL path components containing ../ sequences are directly concatenated to the configured web root directory without any form of normalization or security checks. This fundamental design flaw allows attackers to manipulate file paths through crafted URL requests that bypass standard URL parsing mechanisms, resulting in unauthorized access to sensitive system resources.
The technical implementation of this vulnerability operates at the filesystem level where the HttpFile::setFile() function receives the malformed path directly from the URL parser without any sanitization or boundary enforcement. When the server process executes with root privileges, attackers can exploit this flaw to retrieve critical system files including configuration files, credential stores, private keys, and other sensitive data that would normally be protected by proper file access controls. The vulnerability manifests because the application fails to implement standard security measures such as dot-segment removal, path normalization, or boundary checking that are essential for preventing directory traversal attacks.
From an operational perspective, this vulnerability presents a severe risk to systems running TinyWeb as it allows attackers to bypass authentication mechanisms entirely and directly access system files. The impact extends beyond simple information disclosure to potential system compromise when attackers can obtain private keys, credential stores, or configuration files that may contain database passwords, API keys, or other sensitive authentication tokens. According to the mitre attack framework, this vulnerability aligns with the technique of "Path Traversal" (attack technique T1083) and falls under the weakness category of CWE-22 - Improper Limitation of a Pathname to a Restricted Directory. The vulnerability is particularly dangerous in environments where the web server process runs with elevated privileges, as it provides attackers with direct access to sensitive system resources.
The mitigation strategy for this vulnerability requires immediate implementation of proper input validation and path sanitization measures within the application code. Developers should ensure that all URL path components undergo normalization processing, with dot-segment removal algorithms applied before any file system operations occur. Security controls must include boundary checking mechanisms that prevent traversal beyond the designated web root directory and implement proper access control lists for file system operations. Additionally, the server should be configured to run with minimal required privileges rather than as root, reducing the potential impact of successful exploitation. Organizations should also consider implementing web application firewalls and security monitoring solutions to detect and block suspicious path traversal attempts. The fix must address the core issue in HttpBuilder::buildResponse() by ensuring that all user-supplied path data is properly validated and sanitized before being processed by HttpFile::setFile(), thereby preventing malicious path manipulation from reaching the underlying filesystem layer.
This vulnerability demonstrates the critical importance of input validation and proper security implementation in web applications, as it represents a classic example of how insufficient boundary checking can result in complete system compromise. The flaw's exploitation requires minimal technical expertise and provides significant access to sensitive data, making it particularly attractive to attackers. Organizations deploying TinyWeb or similar lightweight web servers must prioritize patching this vulnerability and implementing comprehensive security measures to prevent unauthorized file system access.