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OpenStack Nova calls qemu-img without format restrictions for resize

High severity GitHub Reviewed Published Feb 18, 2026 to the GitHub Advisory Database • Updated Feb 21, 2026

Package

pip Nova (pip)

Affected versions

>= 32.0.0.0rc1, <= 32.1.0
>= 31.0.0.0rc1, <= 31.2.0
<= 30.2.1

Patched versions

None

Description

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.

References

Published by the National Vulnerability Database Feb 18, 2026
Published to the GitHub Advisory Database Feb 18, 2026
Reviewed Feb 19, 2026
Last updated Feb 21, 2026

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
Low
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:H/A:H

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(13th percentile)

Weaknesses

Incorrect Resource Transfer Between Spheres

The product does not properly transfer a resource/behavior to another sphere, or improperly imports a resource/behavior from another sphere, in a manner that provides unintended control over that resource. Learn more on MITRE.

CVE ID

CVE-2026-24708

GHSA ID

GHSA-m4f3-qp2w-gwh6

Source code

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