CVE-2025-61915 is a vulnerability in the OpenPrinting CUPS (Common Unix Printing System) software, which is widely used on Linux and Unix-like operating systems for managing print jobs and queues. The flaw arises from improper validation of array indexes (CWE-129) during the parsing of configuration files. Specifically, a user with membership in the lpadmin group can access the cups web UI to modify the printing configuration and insert a malicious line. When the cupsd daemon, which runs with root privileges, parses this manipulated configuration, it triggers an out-of-bounds write (CWE-124). This memory corruption can lead to instability or crashes of the cupsd process, resulting in denial of service. The vulnerability requires local privileges (lpadmin group membership) but does not require additional user interaction. The scope is limited to systems running vulnerable versions of CUPS prior to 2.4.15. The issue was publicly disclosed on November 29, 2025, and has been patched in version 2.4.15. No known exploits have been reported in the wild, but the vulnerability’s potential to cause service disruption makes it a concern for environments relying on CUPS for printing services.

For European organizations, the primary impact of CVE-2025-61915 is on the availability of printing services. Organizations with critical printing infrastructure relying on CUPS could experience denial of service if the vulnerability is exploited, potentially disrupting business operations that depend on printing. Although the vulnerability does not directly compromise confidentiality or integrity, the root-level execution context of cupsd means that exploitation could be leveraged as part of a larger attack chain. Organizations in sectors such as government, finance, healthcare, and manufacturing—where printing remains integral—may face operational risks. Additionally, organizations with large Unix/Linux server deployments or managed print services are at risk. The requirement for lpadmin group membership limits the attack surface to users with elevated local privileges, but insider threats or compromised accounts could exploit this vulnerability. Given the widespread use of CUPS in European IT environments, failure to patch could lead to service outages and increased risk exposure.

European organizations should immediately upgrade all CUPS installations to version 2.4.15 or later to remediate this vulnerability. In addition, organizations should audit membership of the lpadmin group to ensure only trusted administrators have this privilege, reducing the risk of exploitation. Implement strict access controls and monitoring on the cups web UI to detect unauthorized configuration changes. Employ host-based intrusion detection systems (HIDS) to monitor cupsd process behavior and alert on crashes or unusual activity. Regularly review and harden printing infrastructure configurations, disabling unnecessary services or interfaces. Consider network segmentation to isolate printing servers from less trusted network zones. Finally, maintain up-to-date backups of configuration files and ensure incident response plans include scenarios involving printing service disruption.