CVE-2026-36453 in Rhymix
Summary
by MITRE • 09/13/2026
Rhymix before 2.1.31 allows insecure direct object reference, aka RVE-2026-1. Arbitrary files can be accessed via extra variables.
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Analysis
by VulDB Data Team • 09/13/2026
The vulnerability identified as RVE-2026-1 in Rhymix versions prior to 2.1.31 represents a critical security flaw classified under the category of Insecure Direct Object References, commonly known by its CWE identifier CWE-85. This type of vulnerability arises when an application exposes internal implementation objects, such as files or database keys, directly to users without proper access control checks. In the specific context of Rhymix, this flaw manifests through the handling of extra variables passed within HTTP requests. The system fails to adequately validate these parameters against a whitelist of allowed resources or verify that the requesting user has permission to access the specified target. Consequently, an attacker can manipulate input data to reference arbitrary files stored on the server's file system, bypassing intended security boundaries and gaining unauthorized read access to sensitive content.
From a technical perspective, the exploitation mechanism relies on the application's failure to sanitize or restrict the values provided in extra variables used for file inclusion or retrieval operations. When a user submits a request containing these parameters, Rhymix processes them directly without sufficient verification of their legitimacy. This lack of validation allows an attacker to construct malicious payloads that traverse directory structures using path traversal sequences such as dot-dot-slash notation. By carefully crafting the input string, an adversary can navigate outside the intended web root or application-specific directories to access configuration files, source code containing hardcoded credentials, database dumps, or other sensitive data residing on the server. This behavior aligns with the ATT&CK technique of T1083, which involves File and Directory Discovery, as well as T1560, Archive Collected Data, if the attacker subsequently attempts to exfiltrate the retrieved information.
The operational impact of this vulnerability is severe, particularly for deployments handling sensitive user data or proprietary business logic. Successful exploitation can lead to a complete compromise of confidentiality, allowing attackers to extract private keys, administrative credentials stored in configuration files, and personal identifiable information from database backups if they are accessible via the file system. Furthermore, access to source code may reveal additional vulnerabilities within the application's own implementation, facilitating further attacks such as remote code execution or SQL injection. The integrity of the system is also at risk, as attackers might use this initial foothold to upload malicious scripts or modify existing files for persistence and lateral movement within the network environment.
To mitigate this vulnerability, administrators must upgrade Rhymix to version 2.1.31 or later, where these input validation mechanisms have been corrected. In environments where immediate patching is not feasible due to operational constraints, temporary mitigations should be implemented at the web server level. This includes configuring strict file access controls that prevent direct execution of PHP files and restricting directory listing capabilities. Additionally, implementing a Web Application Firewall with rules specifically designed to detect and block path traversal attempts can provide an additional layer of defense. It is also recommended to review application code for similar patterns where user-supplied input is used directly in file operations without proper sanitization or allow-listing, ensuring that only predefined, safe values are processed by the system.