CVE-2025-57156 identifies a NULL pointer dereference vulnerability in the owntone-server project, specifically within the dacp_reply_playqueueedit_clear function located in src/httpd_dacp.c. This function is part of the HTTP daemon handling DACP requests, which are used for remote control of audio playback queues. The vulnerability was introduced after version 28.12, notably in commit 6d604a1. When a specially crafted DACP request is sent to the server, the function attempts to access or clear a pointer that is NULL, causing the server process to crash. This results in a denial of service condition, rendering the media server unavailable until restarted. The flaw can be triggered remotely without authentication or user interaction, making it accessible to unauthenticated attackers on the network. While no public exploits are currently known, the vulnerability poses a risk to availability for deployments relying on owntone-server for media streaming or audio control. The lack of a CVSS score indicates the need for an independent severity assessment. The vulnerability does not appear to allow code execution or data leakage, focusing impact on service disruption. The technical root cause is improper handling of null pointers in DACP request processing, a common programming error in C-based network services.

For European organizations, the primary impact of CVE-2025-57156 is the potential for denial of service against owntone-server instances. This can disrupt media streaming services, audio playback control, or other dependent applications, leading to operational downtime and user dissatisfaction. Organizations using owntone-server in corporate, educational, or entertainment environments may experience interruptions in audio services, affecting productivity or customer experience. Although no data breach or integrity compromise is indicated, repeated or targeted exploitation could degrade service reliability. The vulnerability’s remote and unauthenticated nature increases risk, especially in environments where owntone-server is exposed to untrusted networks. Given the growing use of media servers in smart office and IoT contexts, this DoS could indirectly impact broader operational technology. However, the impact is limited to availability and does not extend to confidentiality or integrity of data. The absence of known exploits reduces immediate risk but does not eliminate the threat of future weaponization.

To mitigate CVE-2025-57156, European organizations should first identify all owntone-server deployments within their infrastructure. Immediate steps include restricting network access to the DACP service, ideally isolating it behind firewalls or VPNs to limit exposure to untrusted networks. Administrators should monitor for unusual crashes or service interruptions indicative of exploitation attempts. Since no official patch or update is currently linked, organizations should track the owntone-server project for forthcoming security updates addressing this issue and apply them promptly. As a temporary workaround, disabling or restricting the DACP functionality within owntone-server can prevent exploitation of the vulnerable code path. Additionally, implementing robust service monitoring and automated restart mechanisms can reduce downtime impact. Network intrusion detection systems (NIDS) can be tuned to detect anomalous DACP traffic patterns. Finally, organizations should incorporate this vulnerability into their incident response plans to quickly address potential DoS events.