The vulnerability is in OpenStack Nova prior to certain releases and allows a malicious QCOW header to be written to a root or temporary disk and then used to trigger a resize operation. Because the Flat image backend calls qemu‑img without a format restriction, the resize can overwrite arbitrary files on the host system, potentially destroying critical data or configuration. The weakness is tied to CWE‑669 “Security Function” and CWE‑73 “Path Manipulation.”

Affected systems are compute nodes that use the Flat image backend in OpenStack Nova, with the configuration use_cow_images set to False. The issue applies to Nova versions earlier than 30.2.2, 31.2.1, and 32.1.1.

The CVSS score of 8.2 indicates high severity, though the EPSS score of less than 1% implies a low exploitation likelihood. The vulnerability is not listed in KEV. Attackers need the ability to create and upload a malicious image or QCOW header and must target a compute node configured with the Flat backend, which limits the attack surface to environments that have enabled this feature. Based on the description, it is inferred that the attack vector is internal to the compute service and requires authenticated actions to create or trigger the unsafe resize.