CVE-2025-12748 is a vulnerability identified in the libvirt virtualization management library used in Red Hat Enterprise Linux 10. The issue arises from the order of operations during XML file processing: libvirt parses user-supplied XML files before performing Access Control List (ACL) checks. This design flaw allows a malicious user with limited privileges to submit a specially crafted XML file that triggers excessive memory allocation on the host system. The uncontrolled resource consumption can cause the libvirt process to crash, resulting in a denial-of-service (DoS) condition that impacts the availability of virtualization services. The vulnerability does not compromise confidentiality or integrity, as it does not allow unauthorized data access or modification. Exploitation requires local access with at least limited privileges but does not require user interaction. No public exploits have been reported so far, and the vulnerability was published on November 11, 2025. The CVSS v3.1 score is 5.5 (medium), reflecting the moderate impact and attack complexity. The flaw is particularly relevant in environments where multiple users interact with libvirt-managed virtual machines, such as cloud or hosting providers, as it could be leveraged to disrupt services by exhausting host memory resources.

For European organizations, this vulnerability primarily threatens the availability of virtualization infrastructure managed by libvirt on Red Hat Enterprise Linux 10. Organizations relying on virtualized environments for critical workloads, including cloud service providers, data centers, and enterprises with multi-tenant setups, may experience service disruptions if an attacker exploits this flaw. The denial-of-service condition could lead to downtime, affecting business continuity and potentially causing financial losses or reputational damage. Since the exploit requires local access with limited privileges, insider threats or compromised accounts pose a higher risk. The vulnerability does not expose data confidentiality or integrity, but the interruption of virtualization services can impact dependent applications and services. Given the widespread use of Red Hat Enterprise Linux in European enterprises and public sector organizations, the impact could be significant if not mitigated promptly.

1. Apply official patches from Red Hat as soon as they become available to address the XML parsing order and resource allocation controls in libvirt. 2. Restrict access to libvirt management interfaces and XML submission capabilities to trusted and authorized users only, minimizing the attack surface. 3. Implement strict user privilege management and auditing to detect and prevent unauthorized attempts to submit XML configurations. 4. Monitor system memory usage and libvirt process stability to detect abnormal resource consumption early, enabling rapid response to potential exploitation attempts. 5. Consider deploying resource limits or cgroups to constrain memory usage by libvirt processes, preventing excessive allocation from impacting the host system. 6. In multi-tenant environments, isolate user workloads and enforce strict access controls to reduce the risk of privilege escalation or misuse. 7. Educate system administrators and security teams about this vulnerability and the importance of timely patching and monitoring.