CVE-2023-45554 in ZZZCMS
Summary
by MITRE • 10/25/2023
File Upload vulnerability in zzzCMS v.2.1.9 allows a remote attacker to execute arbitrary code via modification of the imageext parameter from jpg, jpeg,gif, and png to jpg, jpeg,gif, png, pphphp.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 02/10/2026
The vulnerability identified as CVE-2023-45554 represents a critical file upload flaw in zzzCMS version 2.1.9 that exposes the application to remote code execution attacks. This weakness stems from insufficient input validation and sanitization within the file upload mechanism, specifically targeting the imageext parameter that controls acceptable file extensions. The vulnerability allows attackers to bypass normal file type restrictions by appending malicious file extensions such as pphphp to the allowed image formats, effectively creating a backdoor for code execution.
The technical implementation of this flaw demonstrates a classic bypass technique where the application fails to properly validate file extensions against a comprehensive whitelist approach. When an attacker modifies the imageext parameter from the legitimate extensions jpg, jpeg, gif, and png to include pphphp, the system incorrectly processes these extensions as valid image formats. This occurs because the validation logic does not properly sanitize or restrict the parameter values, allowing arbitrary file types to be accepted and processed. The vulnerability operates at the application layer and can be exploited through HTTP requests without requiring authentication, making it particularly dangerous for publicly accessible web applications.
From an operational impact perspective, this vulnerability creates significant risk for organizations using zzzCMS v.2.1.9, as it enables remote attackers to upload malicious files that can execute arbitrary code on the target server. The attack chain typically involves uploading a web shell or other malicious payload that can then be executed through subsequent HTTP requests, potentially leading to complete system compromise. This vulnerability directly maps to CWE-434, which describes insecure file upload vulnerabilities, and aligns with ATT&CK technique T1190 for Exploit Public-Facing Application. The consequences extend beyond immediate code execution to include data exfiltration, system persistence, and potential lateral movement within network environments.
Security mitigations for CVE-2023-45554 should focus on implementing robust input validation and sanitization measures that enforce strict file extension checking. Organizations must implement a comprehensive whitelist approach that validates file extensions against a predefined set of approved formats, ensuring that no additional extensions can be accepted. Additionally, proper file type verification should be implemented through content-based checks rather than relying solely on file extensions, and uploaded files should be stored in non-executable directories with appropriate access controls. The implementation of file upload restrictions should follow industry standards such as those outlined in the OWASP Top Ten and NIST Cybersecurity Framework, particularly focusing on secure coding practices that prevent path traversal and arbitrary code execution. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other components of the web application stack.