CVE-2026-79551 in NVR_4H CH3
Summary
by MITRE • 09/15/2026
Tenda Technology Co., Ltd NVR_4H CH3 v2.1 V27.5.58.6 was discovered to contain a hardcoded cryptographic key.
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Analysis
by VulDB Data Team • 09/15/2026
The discovery of a hardcoded cryptographic key within the Tenda Technology Network Video Recorder model NVR_4H CH3 running firmware version V27.5.58.6 represents a critical failure in secure software development practices. This vulnerability stems from the embedding of static encryption keys directly into the application binary or configuration files, rather than generating unique, random keys for each device instance during manufacturing or first-boot initialization. Such an approach fundamentally undermines the confidentiality and integrity guarantees that cryptographic mechanisms are designed to provide. When a single key is shared across all devices of this specific model and firmware version, it creates a systemic weakness where compromise of one unit can lead to the compromise of all units relying on the same secret material. This practice violates fundamental principles of cryptography which dictate that keys must remain confidential and unique per entity to ensure secure communication channels.
From a technical perspective, hardcoded keys often reside in easily accessible locations within the firmware image, such as plaintext configuration files or unobfuscated binary strings. Attackers with physical access to the device can extract these keys using standard forensic tools by dumping memory contents or analyzing the flash storage partitions. Even without physical access, if the vulnerability allows for remote code execution or unauthorized file read operations through other flaws in the network service stack, an attacker could retrieve the key remotely. The presence of this static credential means that any encrypted traffic generated by the device using this key can be decrypted by anyone who obtains it. This effectively nullifies encryption protections intended to safeguard video streams, user credentials, and administrative commands transmitted over the network or stored on local storage media.
The operational impact of this vulnerability is severe, particularly in environments where privacy and security are paramount, such as residential surveillance systems or small business monitoring setups. An adversary possessing the hardcoded key can perform man-in-the-middle attacks to decrypt live video feeds, exposing sensitive visual data to unauthorized viewers. Furthermore, if the same key is used for authenticating administrative commands, an attacker could potentially inject malicious configuration changes, disable recording functions, or manipulate stored footage without detection. This compromises not only confidentiality but also integrity and availability of the security infrastructure. The risk is amplified because users typically do have control over these keys; they are fixed by the manufacturer and cannot be rotated through standard user interfaces, leaving victims vulnerable until a firmware update addresses the issue.
This flaw aligns with CWE-798: Use of Hard-coded Credentials, which categorizes vulnerabilities where authentication credentials or cryptographic keys are embedded directly into source code or compiled binaries. It also relates to CWE-321: Use of a Key Past its Expiration Date if the key is intended for temporary use but remains static indefinitely. In terms of offensive security frameworks, this vulnerability facilitates attacks categorized under MITRE ATT&CK technique T1552.004: Unsecured Credentials, specifically involving stored credentials that can be extracted from device storage or memory dumps. The exploitation path typically involves initial access through network services followed by credential dumping to achieve further lateral movement or persistent control over the surveillance system.
Mitigation strategies must focus on both immediate remediation and long-term architectural improvements. For end-users, the primary defense is to apply any available firmware updates released by Tenda Technology that replace the hardcoded key with a dynamically generated one unique to each device. If no update is currently available, users should isolate these devices from untrusted networks using network segmentation or firewalls to limit exposure to potential attackers. Additionally, changing default administrative passwords and disabling remote access features can reduce the attack surface for retrieving such credentials. For manufacturers, this incident highlights the necessity of implementing secure key management systems that utilize hardware security modules or trusted platform modules to generate and store unique keys per device during production. Adhering to industry standards like NIST SP 800-57 regarding cryptographic key lifecycle management is essential to prevent recurrence of such critical flaws in future firmware releases.