CVE-2026-24469 is a path traversal vulnerability classified under CWE-22 affecting frustratedProton's http-server versions 1.0 and earlier. The server is implemented in C++ and handles HTTP/1.1 requests. The vulnerability exists in the RequestHandler::handleRequest method, where the filename variable derived from the user-controlled URL path is concatenated directly to the files_directory base path without proper sanitization or normalization. This allows an attacker to craft malicious HTTP GET requests containing '../' sequences to traverse directories outside the intended root directory and read arbitrary files on the server's filesystem. Since the flaw does not require authentication or user interaction, it can be exploited remotely by any unauthenticated attacker with network access to the server. The vulnerability impacts confidentiality by exposing sensitive files but does not affect integrity or availability. At the time of publication, no patch or fix was available, increasing the risk for organizations relying on this software. Although no known exploits have been reported in the wild, the high CVSS score of 7.5 reflects the ease of exploitation and potential impact. The lack of input validation and path normalization is a common security oversight in web servers, making this vulnerability a critical concern for deployments of frustratedProton http-server in production environments.

For European organizations, this vulnerability poses a significant risk of unauthorized disclosure of sensitive information, including configuration files, credentials, or proprietary data stored on servers running vulnerable versions of frustratedProton http-server. This can lead to further compromise if attackers gain access to sensitive internal data or credentials. Sectors such as government, finance, healthcare, and critical infrastructure that rely on this HTTP server for web services or APIs are particularly at risk. The exposure of confidential data can result in regulatory penalties under GDPR, reputational damage, and operational disruptions. Since exploitation requires only network access and no authentication, attackers can easily scan for vulnerable servers and extract data remotely. The absence of a patch at the time of disclosure means organizations must rely on compensating controls, increasing operational complexity. The vulnerability does not directly impact system integrity or availability, but the confidentiality breach alone can have severe consequences in regulated environments.

European organizations should immediately audit their environments to identify any deployments of frustratedProton http-server version 1.0 or earlier. Since no official patch is available, organizations must implement strict input validation and path normalization within their HTTP server configurations or application code to sanitize URL paths and reject any requests containing directory traversal sequences such as '../'. Employing web application firewalls (WAFs) with rules to detect and block path traversal attempts can provide an additional layer of defense. Restricting file system permissions to limit the HTTP server's access to only necessary directories reduces the potential impact of successful traversal. Network segmentation and limiting exposure of vulnerable servers to untrusted networks can reduce attack surface. Monitoring HTTP logs for suspicious requests containing traversal patterns and setting up alerting mechanisms can help detect exploitation attempts. Organizations should also engage with the vendor or community to track patch releases and plan timely updates once available. Finally, consider deploying runtime application self-protection (RASP) solutions that can detect and block malicious input in real time.