CVE-2025-3177 in FastCMS
Summary
by MITRE • 04/03/2025
A vulnerability was found in FastCMS 0.1.5. It has been declared as critical. This vulnerability affects unknown code of the component JWT Handler. The manipulation leads to use of hard-coded cryptographic key
. The attack can be initiated remotely. The complexity of an attack is rather high. The exploitation appears to be difficult. The exploit has been disclosed to the public and may be used.
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Analysis
by VulDB Data Team • 06/21/2026
This critical vulnerability in FastCMS 0.1.5 resides within the JWT Handler component and represents a severe cryptographic weakness that undermines the entire security framework of the application. The flaw manifests through the use of a hard-coded cryptographic key, which violates fundamental security principles and creates a catastrophic exposure point for attackers. This vulnerability type maps directly to CWE-327, which specifically addresses the use of hard-coded cryptographic keys, and falls under the broader category of weak cryptography issues that have been consistently flagged as high-risk by security organizations worldwide. The presence of such a hard-coded key means that any individual who discovers this value can immediately bypass authentication mechanisms and gain unauthorized access to the system.
The remote exploitation capability of this vulnerability significantly amplifies its potential impact, as attackers need not have physical access to the system or local network privileges to exploit the flaw. This remote attack vector aligns with ATT&CK technique T1213.002, which covers credentials from password stores, and demonstrates how weak cryptographic implementations can create entry points for attackers to escalate privileges and gain persistent access. The high attack complexity and difficult exploitation requirements suggest that while the vulnerability exists, attackers must possess a certain level of technical expertise and may need to perform additional reconnaissance to identify the specific hard-coded key within the JWT handler component. However, the public disclosure of the exploit means that this barrier has been effectively lowered for malicious actors who may not possess advanced technical skills.
The operational impact of this vulnerability extends far beyond simple unauthorized access, as JWT tokens are typically used for session management, authentication, and authorization across web applications. When a hard-coded key is used, attackers can forge valid tokens, impersonate legitimate users, and potentially access sensitive data, modify content, or even escalate their privileges to administrative levels within the FastCMS environment. This represents a complete breakdown of the authentication and authorization mechanisms that JWT tokens are designed to provide. The vulnerability affects the core security infrastructure of the application, potentially allowing attackers to compromise not just individual user accounts but the entire CMS system, including administrative interfaces and content management capabilities.
Organizations using FastCMS 0.1.5 must implement immediate mitigations to address this critical flaw, beginning with the generation and deployment of truly random, cryptographically secure keys for JWT token handling. This remediation directly addresses CWE-327 requirements for proper key management and cryptographic implementation. The solution involves replacing the hard-coded key with dynamically generated keys that are properly stored and managed according to security best practices, including adherence to NIST SP 800-57 guidelines for key management. Additionally, implementing proper key rotation mechanisms and ensuring that cryptographic keys are not embedded within source code or configuration files will help prevent similar issues from occurring in the future. System administrators should also conduct comprehensive security audits to identify any other instances of hard-coded credentials or cryptographic material within the application, as this vulnerability may indicate broader security weaknesses in the codebase that require immediate attention and remediation.