CVE-2025-57155 is a remote Denial of Service vulnerability found in the owntone-server, an open-source media server software. The flaw resides in the daap_reply_groups function within the HTTP daemon (httpd_daap.c), where a NULL pointer dereference can occur. This happens when the function attempts to access or manipulate data through a pointer that has not been properly initialized or has been set to NULL, leading to a crash of the server process. The vulnerability affects versions newer than 28.2, as indicated by the commit 5e6f19a, but no specific patch or fixed version has been released publicly. Because the vulnerability can be triggered remotely without authentication or user interaction, an attacker can cause the server to crash simply by sending crafted requests to the affected endpoint. This results in a Denial of Service condition, disrupting the availability of the media server and potentially impacting users relying on the service for streaming or sharing media content. No known exploits have been reported in the wild, but the vulnerability's nature makes it a candidate for exploitation once weaponized. The lack of a CVSS score means severity must be assessed based on the impact on availability, ease of exploitation, and scope of affected systems. Owntone-server is used in various environments, including personal, small business, and community media sharing setups, which could be targeted by attackers aiming to disrupt services or cause reputational damage.

For European organizations, the primary impact of CVE-2025-57155 is the potential disruption of media streaming and sharing services provided by owntone-server. This could affect internal communications, media distribution, or customer-facing services relying on this software. The Denial of Service condition could lead to downtime, loss of productivity, and negative user experience. In sectors where media servers support critical workflows or public services, such as education, cultural institutions, or media companies, the impact could be more pronounced. Additionally, repeated exploitation attempts could increase operational costs due to incident response and recovery efforts. While the vulnerability does not directly compromise confidentiality or integrity, the availability impact alone can be significant, especially if exploited at scale or during peak usage times. European organizations with limited IT resources or those relying on community-supported open-source solutions may face challenges in timely patching and mitigation.

1. Monitor official owntone-server repositories and security advisories for patches or updates addressing CVE-2025-57155 and apply them promptly once available. 2. Restrict network access to the owntone-server HTTP daemon by implementing firewall rules or network segmentation to limit exposure to trusted users or internal networks only. 3. Employ intrusion detection and prevention systems (IDS/IPS) to detect and block anomalous or malformed requests targeting the daap_reply_groups function or related endpoints. 4. Regularly audit and review server logs for unusual activity that could indicate attempted exploitation. 5. Consider deploying rate limiting or connection throttling on the affected service to reduce the risk of DoS attacks. 6. If feasible, temporarily disable or replace the affected service with alternative solutions until a patch is available. 7. Educate IT staff about the vulnerability and ensure incident response plans include steps for handling DoS incidents related to this software.