CVE-2026-0915 is a vulnerability classified under CWE-908 (Use of Uninitialized Resource) affecting the GNU C Library (glibc) versions from 2.0 up to 2.42. The issue arises when the functions getnetbyaddr or getnetbyaddr_r are invoked with an nsswitch.conf configuration that specifies the DNS backend for network name resolution. Specifically, if a query is made for a zero-valued network address, the library may inadvertently leak uninitialized stack memory contents to the configured DNS resolver. This leakage occurs because the internal handling of network queries does not properly initialize all memory buffers before use, leading to exposure of potentially sensitive data residing on the stack. The vulnerability is remotely exploitable without requiring any privileges or user interaction, as it can be triggered by sending crafted network queries that invoke these functions. The impact is primarily on confidentiality, as attackers may gain access to sensitive information from the leaked stack data. The vulnerability does not affect integrity or availability directly. Although no public exploits are known at this time, the widespread use of glibc in Linux-based systems, including servers and network devices, makes this a significant concern. The lack of available patches at the time of disclosure necessitates immediate configuration review and monitoring to mitigate risk.

For European organizations, the confidentiality breach posed by CVE-2026-0915 could lead to exposure of sensitive internal data, including credentials, cryptographic keys, or other critical information residing in stack memory. This is particularly concerning for sectors such as finance, healthcare, telecommunications, and government, where data privacy and security are paramount. The vulnerability could be exploited remotely, increasing the attack surface for organizations with externally facing services that rely on glibc for network name resolution. While the vulnerability does not directly compromise system integrity or availability, the leaked information could facilitate further attacks, including lateral movement or privilege escalation. The impact is amplified in environments where DNS queries are logged or monitored, as attackers might intercept or analyze DNS traffic to extract leaked data. Given the extensive deployment of Linux-based systems across European enterprises and public sector infrastructure, the potential for widespread data leakage is significant if unmitigated.

1. Immediately review and audit the nsswitch.conf configuration on all affected systems to identify and modify entries that specify the DNS backend for network queries, especially those involving getnetbyaddr or getnetbyaddr_r calls. 2. Where possible, temporarily disable or restrict the use of the DNS backend for network name resolution until patches are available. 3. Monitor DNS resolver traffic for unusual or unexpected queries that may indicate exploitation attempts or data leakage. 4. Implement network-level controls such as DNS query filtering and logging to detect anomalous patterns. 5. Apply patches or updates from the GNU C Library project as soon as they are released to address this vulnerability. 6. Conduct internal penetration testing and code audits to identify any indirect exposure resulting from this vulnerability. 7. Educate system administrators and security teams about the specific conditions that trigger the vulnerability to ensure rapid detection and response. 8. Consider deploying runtime memory protection tools or stack canaries that may help detect exploitation attempts involving uninitialized memory usage.