CVE-2026-63303 in Quick.CMS
Summary
by MITRE • 07/28/2026
A Path Traversal vulnerability exists in Quick.CMS through the URI path component of HTTP requests, where the server fails to normalize dot-dot-slash (../) sequences before resolving and serving the requested file. An authenticated attacker with admin privileges can use this vulnerability to read contents of files located in the sibling directory of the webroot via a crafted HTTP request containing ../ sequences in the URI.
The vendor assessed the likelihood of exploitation as very low and determined that a fix is not necessary.
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Analysis
by VulDB Data Team • 07/28/2026
This vulnerability represents a classic path traversal flaw that enables unauthorized file access through improper input validation in the Quick.CMS web application. The issue manifests when the server processes HTTP requests containing URI path components with dot-dot-slash sequences without adequate normalization or sanitization. When an authenticated administrator submits a crafted request with ../ sequences in the URI path, the application fails to properly resolve these references, allowing access to files outside the intended webroot directory structure. This type of vulnerability falls under CWE-22 Path Traversal and specifically aligns with ATT&CK technique T1566.002 Exploitation of Remote Services where adversaries leverage web application weaknesses to gain unauthorized access to sensitive information.
The technical implementation of this flaw demonstrates a failure in the server's file resolution logic where input validation occurs too late in the processing pipeline or not at all. During normal operation, when Quick.CMS receives an HTTP request, it should normalize all path components before attempting to resolve and serve files from the filesystem. However, the application processes the URI path directly without canonicalizing the ../ sequences, which allows attackers to traverse up the directory hierarchy. This weakness creates a direct pathway for information disclosure where an attacker can access configuration files, database credentials, application source code, or other sensitive data stored in adjacent directories relative to the webroot.
The operational impact of this vulnerability is significant despite the vendor's assessment of low exploitation likelihood. While authenticated access is required, administrative privileges provide attackers with substantial leverage to compromise system integrity and confidentiality. An attacker with admin credentials could potentially extract database connection strings, application configuration files containing cryptographic keys, or sensitive business data stored in sibling directories. The vulnerability also creates potential for further exploitation by enabling attackers to read system files that might contain additional attack vectors or sensitive information about the underlying infrastructure. This represents a critical weakness in the application's security architecture as it allows privilege escalation through file system access rather than direct code execution or authentication bypass mechanisms.
The vendor's determination that this issue does not require a fix appears to underestimate both the potential for exploitation and the risk associated with authenticated attackers having elevated privileges. The presence of any path traversal vulnerability in web applications should be addressed regardless of perceived exploitation likelihood, as these flaws often serve as stepping stones for more sophisticated attacks. Organizations should implement proper input validation and path normalization at multiple layers including application code, web server configurations, and potentially network-level controls. Recommended mitigations include implementing strict file access controls, using secure coding practices that validate and sanitize all user-supplied input, deploying web application firewalls, and conducting regular security assessments to identify similar vulnerabilities in the application's attack surface. The vulnerability also highlights the importance of principle of least privilege in web applications where even administrative functions should be subject to proper input validation and access controls.