Introduction
Backup data from Samsung devices can be exposed to attackers on the same WiFi network if users rely on outdated versions of Smart Switch. CVE-2025-21078 demonstrates how a single cryptographic oversight can undermine the confidentiality of sensitive user data during wireless transfers. This vulnerability is highly relevant for organizations and individuals who use Smart Switch for device migration or backup operations, especially in environments where network adjacency is common.
Samsung Smart Switch is a widely used application for transferring data between Samsung devices. It supports both wired and wireless transfers, making it a convenient tool for millions of users worldwide. The application's popularity and integration into Samsung's device ecosystem mean that vulnerabilities affecting Smart Switch can have broad impact across the mobile user base.
Technical Information
CVE-2025-21078 affects Samsung Smart Switch versions prior to 3.7.68.6. The vulnerability is rooted in the application's use of insufficiently random values when generating the secretKey parameter, which is used to secure backup data during wireless transfers. Specifically, the random number generator employed for secretKey creation does not provide enough entropy, making the resulting key values predictable to an attacker with network adjacency.
This issue is classified under CWE-330 (Use of Insufficiently Random Values). In practice, the flaw allows an attacker on the same network segment as the victim to observe or infer the secretKey used during a Smart Switch wireless transfer. By leveraging statistical analysis or brute-force techniques, the attacker can predict the secretKey and gain unauthorized access to the backup data being transferred. The attack does not require prior compromise of the device or user interaction beyond being present on the same network during the transfer event.
The root cause is a failure to use a cryptographically secure pseudo-random number generator (CSPRNG) or to properly seed the generator with sufficient entropy. This results in a secretKey space that is small enough to allow feasible prediction or brute-force attacks. No public code snippets or detailed PoC are available for this vulnerability.
Patch Information
In the November 2025 security update, Samsung addressed several vulnerabilities across its applications and services. One notable fix pertains to the Samsung Account application, which previously had an issue with handling insufficient permissions or privileges. This flaw allowed local attackers to access sensitive data within the Samsung Account, provided they could interact with the device.
To mitigate this vulnerability, Samsung introduced enhanced authorization verification logic in version 15.5.00.18 of the Samsung Account app. This improvement ensures that only users with the appropriate permissions can access specific data, effectively preventing unauthorized access.
By implementing these security measures, Samsung reinforces the integrity of its applications, safeguarding user data against potential threats.
Patch source: Samsung Mobile Security November 2025
Affected Systems and Versions
- Samsung Smart Switch versions prior to 3.7.68.6 are affected
- All configurations using wireless transfer on these versions are vulnerable
- The vulnerability does not affect versions 3.7.68.6 and later
Vendor Security History
Samsung has experienced several notable vulnerabilities in Smart Switch throughout 2025, including issues related to authentication bypass and improper backup data protection. The company maintains a regular monthly security update cycle and has demonstrated timely patch releases in response to reported vulnerabilities. However, the recurrence of cryptographic and authentication flaws in Smart Switch suggests ongoing challenges in secure development and threat modeling for this application.
