CVE-2025-55972 is a vulnerability affecting TCL Smart TVs that implement a UPnP/DLNA MediaRenderer service. The flaw lies in the handling of the SetAVTransportURI SOAP requests sent to the UPnP control endpoint. An attacker can exploit this vulnerability remotely and without authentication by flooding the device with malformed or oversized SetAVTransportURI requests. This causes the device to enter a Denial of Service (DoS) state, rendering the TV unresponsive to all forms of operation, including manual controls and reboots. The denial persists as long as the attack continues, effectively disabling the device's functionality. The vulnerability exploits the device's inability to properly validate or handle excessive or malformed input in the UPnP service, which is commonly used for media streaming and control. Since UPnP is often enabled by default on smart TVs to facilitate media sharing and control within local networks, this vulnerability can be triggered remotely if the attacker can reach the device's UPnP endpoint, potentially even from outside the local network if the device is exposed or if the attacker has compromised the local network. No patches or fixes are currently available, and no known exploits have been reported in the wild as of the publication date. The absence of a CVSS score indicates that the vulnerability is newly disclosed and has not yet been fully assessed for severity by standard scoring systems.

For European organizations, especially those deploying TCL Smart TVs in conference rooms, public spaces, or employee areas, this vulnerability poses a risk of service disruption. An attacker could remotely disable TVs used for presentations, digital signage, or communication, causing operational interruptions. In environments where TVs are integrated into broader AV or IoT management systems, the DoS condition could cascade into wider disruptions. Although the vulnerability does not directly compromise confidentiality or integrity, the loss of availability can impact business continuity and user productivity. Additionally, if attackers leverage this vulnerability as part of a larger attack chain, it could facilitate distraction or denial of service during critical operations. The fact that the attack requires no authentication and can be executed remotely increases the threat level, especially in scenarios where network segmentation or device exposure is inadequate. European organizations with less stringent network controls or those using TCL Smart TVs in sensitive or high-availability environments are particularly vulnerable to operational impacts.

To mitigate this vulnerability, European organizations should first assess the exposure of TCL Smart TVs on their networks, particularly the accessibility of UPnP services. Network segmentation should be enforced to isolate smart TVs from untrusted networks and restrict UPnP traffic to trusted devices only. Disabling UPnP services on the TVs or network devices where feasible can significantly reduce attack surface. Monitoring network traffic for unusual or excessive SOAP requests targeting UPnP endpoints can help detect ongoing attacks. Organizations should also engage with TCL or authorized vendors to obtain firmware updates or patches once available. Until patches are released, implementing firewall rules to block malformed or oversized SOAP requests and rate-limiting UPnP traffic can help mitigate exploitation. Additionally, educating IT staff about this vulnerability and incorporating it into incident response plans will improve readiness. For environments where TVs are critical, consider deploying alternative devices or backup systems to maintain availability during potential attacks.