CVE-2025-59451 identifies a vulnerability in the YoSmart YoLink application related to incorrect authorization due to session tokens that have unexpectedly long lifetimes. This issue is categorized under CWE-863, which involves authorization bypass or incorrect authorization logic. The vulnerability allows an attacker with low privileges to maintain an active session for an extended period, beyond what is typically expected or intended by the application’s security design. The CVSS v3.1 score is 3.5 (low), reflecting that the attack vector is network-based (AV:N), requires high attack complexity (AC:H), and low privileges (PR:L), with no user interaction (UI:N). The scope is changed (S:C), indicating that the vulnerability affects resources beyond the initially authorized scope. The impact is limited to integrity (I:L), with no confidentiality (C:N) or availability (A:N) impact. This means an attacker could potentially perform unauthorized actions or maintain unauthorized access for longer durations but cannot directly exfiltrate data or disrupt service. The vulnerability is present in all versions up to 2025-10-02, with no patches currently available and no known exploits in the wild. The root cause is the session management design flaw where tokens do not expire or refresh appropriately, allowing sessions to persist longer than intended. This can facilitate unauthorized actions if an attacker gains access to a session token or compromises a low-privilege account. The YoLink application is used primarily in IoT and smart home environments, where session management is critical to prevent unauthorized control of connected devices.

For European organizations, the primary impact of this vulnerability lies in the potential for prolonged unauthorized access to IoT devices managed via the YoLink application. This could lead to integrity issues such as unauthorized control or manipulation of smart home or building automation devices. While confidentiality and availability are not directly impacted, the ability to maintain sessions longer than intended increases the attack surface and risk of lateral movement or privilege escalation within the IoT ecosystem. Organizations relying on YoLink for critical automation or security functions may face operational risks if attackers exploit this flaw. Additionally, regulatory compliance under GDPR may be indirectly affected if unauthorized access leads to misuse of personal data collected by IoT devices. The lack of known exploits reduces immediate risk, but the vulnerability should be addressed proactively to prevent future exploitation.

To mitigate this vulnerability, organizations should implement strict session management policies, including reducing session token lifetimes and enforcing automatic expiration or renewal mechanisms. Network segmentation should be employed to isolate IoT devices and limit exposure to potential attackers. Monitoring and logging of session durations and unusual access patterns can help detect exploitation attempts. Users should be educated to use strong authentication methods and avoid sharing session tokens. Organizations should track vendor communications closely and apply patches or updates as soon as they become available. Additionally, consider implementing multi-factor authentication (MFA) for access to the YoLink application where possible to reduce the risk of unauthorized session use. If feasible, temporarily disabling or limiting remote access to the YoLink application until a fix is released can further reduce risk.