CVE-2025-70520 in x7a firmware
Summary
by MITRE • 10/07/2026
The websocket handler of Fanvil x7a firmware version 2.6.0.1182 does not enforce proper authentication restrictions against sessionless users. The lack of restrictions grants anyone the ability to view any device resources such as operational logs or perform diagnostic requests.
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Analysis
by VulDB Data Team • 10/07/2026
The vulnerability identified in Fanvil X7A IP phone firmware version 2.6.0.1182 represents a critical failure in access control mechanisms within the device's websocket handler component. This flaw stems from an insufficient implementation of authentication protocols, specifically allowing unauthenticated or sessionless users to interact with sensitive administrative interfaces over WebSocket connections. In modern networked devices like IP phones, secure communication channels are essential for maintaining system integrity and protecting user privacy. The absence of proper enforcement means that any entity capable of reaching the device on the network can initiate websocket sessions without providing valid credentials, effectively bypassing security controls designed to restrict access to privileged functions.
From a technical perspective, this issue classifies as an improper authentication vulnerability where the server fails to verify the identity or authorization level of the client before processing requests. The websocket handler, which facilitates real-time bidirectional communication between the device and management systems or remote administration tools, does not validate session tokens or require login credentials for certain endpoints. This oversight allows attackers who have network access to the subnet containing the vulnerable devices to exploit this gap directly. By sending specific diagnostic or log retrieval requests over an unauthenticated websocket connection, external actors can extract sensitive operational data that should be protected by role-based access controls.
The operational impact of this vulnerability is significant for organizations relying on Fanvil X7A phones for their communication infrastructure. Attackers with local network access can view operational logs which may contain detailed information about call histories, user activities, and system configurations. Furthermore, the ability to perform diagnostic requests could expose internal network topology details or device states that aid in further reconnaissance. This level of exposure compromises confidentiality and potentially availability if malicious actors use this access to disrupt services or gather intelligence for more sophisticated attacks such as social engineering or targeted phishing campaigns against employees based on observed communication patterns.
This vulnerability aligns with Common Weakness Enumeration (CWE) ID 287, which describes Improper Authentication, where an actor is able to impersonate another user by failing to properly authenticate their identity. Additionally, it relates to CWE 359 regarding Exposure of Private Information Through Security Misconfiguration, as the lack of access control leads to unintended data disclosure. In terms of MITRE ATT&CK framework mapping, this behavior corresponds to techniques under Initial Access and Discovery phases, particularly T1078 Valid Accounts if credentials were previously stolen but not required here, or more accurately T1539 Steal Web Session Cookie if session hijacking was involved, though in this case it is direct unauthenticated access. It also touches upon T1213 Data from Information Repositories since logs and diagnostics are being accessed without authorization.
Mitigation strategies for this vulnerability primarily involve applying the latest firmware updates provided by Fanvil that address these authentication gaps. Administrators should ensure all devices on their network are patched to versions where websocket handlers enforce strict session validation and credential checks before processing sensitive requests. In environments where immediate patching is not feasible, implementing network segmentation can help isolate vulnerable IP phones from general user traffic, restricting access only to trusted management subnets. Additionally, deploying intrusion detection systems that monitor for unusual websocket activity patterns or unauthorized diagnostic queries can provide an additional layer of defense against exploitation attempts until the underlying software flaw is resolved through official vendor updates.