OpenStack Nova calls qemu-img without format restrictions for resize
An issue was discovered in OpenStack Nova before 30.2.2, 31 before 31.2.1, and 32 before 32.1.1. By writing a malicious QCOW header to a root or ephemeral disk and then triggering a resize, a user may convince Nova's Flat image backend to call qemu-img without a format restriction, resulting in an unsafe image resize operation that could destroy data on the host system. Only compute nodes using the Flat image backend (usually configured with use_cow_images=False) are affected.
02 / AFFECTED SOFTWARE
Affected packages
134 explicit affected versions
134 explicit affected versions
04 / EVIDENCE
Source records
An issue was discovered in OpenStack Nova before 30.2.2, 31 before 31.2.1, and 32 before 32.1.1. By writing a malicious QCOW header to a root or ephemeral disk and then triggering a resize, a user may convince Nova's Flat image backend to call qemu-img without a format restriction, resulting in an unsafe image resize operation that could destroy data on the host system. Only compute nodes using the Flat image backend (usually configured with use_cow_images=False) are affected.
An issue was discovered in OpenStack Nova before 30.2.2, 31 before 31.2.1, and 32 before 32.1.1. By writing a malicious QCOW header to a root or ephemeral disk and then triggering a resize, a user may convince Nova's Flat image backend to call qemu-img without a format restriction, resulting in an unsafe image resize operation that could destroy data on the host system. Only compute nodes using the Flat image backend (usually configured with use_cow_images=False) are affected.
05 / REFERENCES
Further evidence
- https://bugs.launchpad.net/nova/+bug/2137507
- https://github.com/openstack/nova
- https://github.com/openstack/nova/commit/3eba22ff09c81a61750fbb4882e5f1f01a20fdf5
- https://lists.debian.org/debian-lts-announce/2026/02/msg00025.html
- https://nvd.nist.gov/vuln/detail/CVE-2026-24708
- https://www.openwall.com/lists/oss-security/2026/02/17/7
- https://github.com/advisories/GHSA-m4f3-qp2w-gwh6
- https://pypi.org/project/nova