CVE-2026-0915 is a vulnerability classified under CWE-908 (Use of Uninitialized Resource) found in the GNU C Library (glibc), versions 2.0 through 2.42. The issue arises when the functions getnetbyaddr or getnetbyaddr_r are invoked with a system configuration (nsswitch.conf) that specifies the DNS backend for network name resolution. Specifically, when a query is made for a zero-valued network, the library may leak uninitialized stack memory contents to the DNS resolver. This leakage occurs because the internal code paths handling these queries do not properly initialize certain stack variables before use, causing potentially sensitive data to be sent out during DNS resolution. The vulnerability primarily threatens confidentiality by exposing stack data, which could include sensitive information such as memory pointers, credentials, or other runtime data. Exploitation requires the attacker to trigger network queries for zero-valued networks on a vulnerable system configured to use DNS for network lookups, which may limit the attack surface. No authentication is required, but user interaction or specific system configurations are necessary. No CVSS score has been assigned yet, and no known exploits have been reported in the wild. The vulnerability affects a fundamental system library widely used in Linux and Unix-like operating systems, making it relevant for many server and embedded environments. The lack of a patch link indicates that fixes may still be pending or in development.

The primary impact of CVE-2026-0915 is the unintended disclosure of stack memory contents, which can lead to information leakage. For European organizations, this could expose sensitive data processed or stored in memory, potentially aiding attackers in further exploitation such as privilege escalation or lateral movement. Since glibc is a core component in most Linux distributions, many servers, workstations, and embedded devices across Europe could be affected, especially those using DNS-based network resolution in nsswitch.conf. Confidentiality is the main concern, while integrity and availability impacts are minimal. The vulnerability could be leveraged in targeted attacks against critical infrastructure, government systems, or enterprises relying on vulnerable Linux environments. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits once patches are released. The impact is heightened in sectors with strict data protection requirements under GDPR and other regulations, where data leakage can have legal and reputational consequences.

To mitigate CVE-2026-0915, European organizations should: 1) Monitor for and apply official glibc patches as soon as they become available from trusted Linux distribution vendors or the GNU project. 2) Temporarily modify the nsswitch.conf configuration to avoid using the DNS backend for network lookups, especially for systems that do not require this functionality. 3) Audit and restrict network queries that could trigger zero-valued network lookups, minimizing exposure. 4) Employ network monitoring to detect unusual DNS query patterns that might indicate exploitation attempts. 5) Use memory protection and address space layout randomization (ASLR) to reduce the usefulness of leaked stack data. 6) Maintain up-to-date intrusion detection and prevention systems to identify suspicious activity related to DNS queries. 7) Educate system administrators about the vulnerability and encourage prompt patch management. These steps go beyond generic advice by focusing on configuration changes and active monitoring tailored to the vulnerability's exploitation vector.