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CVE-2026-24708 OpenStack CVE debrief

CVE-2026-24708 is a high-severity vulnerability in OpenStack Nova's Flat image backend. By writing a malicious QCOW header to a root or ephemeral disk and triggering a resize operation, a user can convince Nova to perform an unsafe image resize, potentially destroying data on the host system. This issue affects compute nodes configured with use_cow_images=False. The vulnerability was publicly disclosed on February 18, 2026, and has a CVSS score of 8.2. Affected versions include OpenStack Nova before 30.2.2, 31 before 31.2.1, and 32 before 32.1.1.

Vendor
OpenStack
Product
Nova
CVSS
HIGH 8.2
CISA KEV
Not listed in stored evidence
Original CVE published
2026-02-18
Original CVE updated
2026-06-30
Advisory published
2026-02-18
Advisory updated
2026-06-30

Who should care

OpenStack Nova administrators and users with access to compute nodes using the Flat image backend should be aware of this vulnerability. Specifically, those with use_cow_images=False configured are at risk. Security teams monitoring for potential data destruction attacks on OpenStack deployments should prioritize patching or mitigating this vulnerability.

Technical summary

The vulnerability exists in OpenStack Nova's Flat image backend. A malicious user can write a crafted QCOW header to a disk and then trigger a resize operation. This can lead to Nova's qemu-img process being executed without proper format restrictions, allowing for potential data destruction on the host system. The issue arises from the lack of format validation when using the Flat backend, which is typically configured with use_cow_images=False. Successful exploitation requires user-level access to create and manipulate disk images.

Defensive priority

High priority should be given to patching OpenStack Nova deployments using the Flat image backend. Administrators should update to versions 30.2.2, 31.2.1, or 32.1.1, or later, as soon as possible. In the interim, consider using the Cinder image backend or enabling use_cow_images=True as a mitigating control.

Recommended defensive actions

  • Apply patches to OpenStack Nova to address the vulnerability.
  • Review and update OpenStack Nova configurations to use a secure image backend.
  • Monitor for suspicious disk manipulation activities.
  • Implement additional access controls to limit user-level disk image creation and manipulation.
  • Consider temporarily disabling the Flat image backend if not essential to operations.

Evidence notes

The CVE record and NVD details were obtained from official sources. Additional information was gathered from OpenStack bug reports and security advisories. The CVSS score of 8.2 indicates a high severity level. Limited information is available on potential exploit attempts or affected systems.

Official resources

This article was AI-assisted and based on the supplied source corpus.