CVE-2025-12748 is a vulnerability in libvirt, a widely used virtualization management tool, specifically affecting Red Hat Enterprise Linux 10. The issue arises because libvirt processes user-supplied XML files before performing Access Control List (ACL) checks. This sequence allows a malicious user with limited permissions to submit a specially crafted XML file that triggers libvirt to allocate excessive amounts of memory on the host system. The uncontrolled resource allocation can overwhelm system memory, causing the libvirt process to crash and resulting in a denial-of-service (DoS) condition. The vulnerability impacts the availability of the virtualization management service but does not compromise confidentiality or integrity. Exploitation requires local access with limited privileges but does not require user interaction. The CVSS 3.1 base score is 5.5 (medium severity), reflecting the local attack vector, low complexity, required privileges, and the impact limited to availability. No public exploits have been reported yet. The flaw highlights a design weakness where input validation and ACL enforcement are not properly ordered, allowing resource exhaustion attacks. This vulnerability is particularly relevant for environments where multiple users have limited access to libvirt-managed resources, such as shared hosting or multi-tenant cloud platforms.

For European organizations, this vulnerability poses a risk primarily to the availability of virtualization infrastructure. Organizations using Red Hat Enterprise Linux 10 with libvirt for managing virtual machines could experience service disruptions if an attacker exploits this flaw to crash libvirt processes. This could lead to downtime of critical virtualized services, impacting business continuity and operational efficiency. Sectors relying heavily on virtualization, such as financial services, telecommunications, and cloud service providers, may face increased risk. Although the vulnerability does not expose sensitive data or allow unauthorized changes, the denial-of-service could indirectly affect service-level agreements and regulatory compliance, especially under GDPR requirements for availability and resilience. The requirement for local access limits the attack surface but does not eliminate risk in environments where multiple users or automated systems have limited privileges. The absence of known exploits reduces immediate risk but does not preclude future attacks.

Organizations should prioritize applying official patches from Red Hat as soon as they become available to address this vulnerability. In the interim, administrators can restrict the ability to submit XML files to trusted users only and implement strict input validation or sandboxing mechanisms for XML processing. Monitoring memory usage and libvirt process stability can help detect early signs of exploitation attempts. Limiting the number of users with access to libvirt and enforcing the principle of least privilege reduces the risk of exploitation. Additionally, consider deploying resource limits (e.g., cgroups or systemd resource controls) on libvirt processes to prevent excessive memory consumption. Regularly auditing virtualization management configurations and access controls will help maintain a secure environment. Finally, organizations should prepare incident response plans for potential DoS events affecting virtualization infrastructure.