---
id: "CVE-2026-46448"
page: "https://infrastack.ai/live/CVE-2026-46448"
kind: "vulnerability"
aliases: ["CVE-2026-46448", "GHSA-mfg3-p6m3-gjgr"]
title: "OpenStack Nova: Nova scheduler hint injection bypasses Placement resource claims and scheduling constraints"
severity: "high"
cvss: 8.5
epss: 0.00272
exploited: false
status: "open"
category: "infrastructure"
products: [{"name": "nova", "fixed": [], "affected": ">= 18.0.0, <= 31.3.0", "ecosystem": "pypi"}, {"name": "nova", "fixed": ["32.2.1"], "affected": ">= 32.0.0, < 32.2.1", "ecosystem": "pypi"}, {"name": "nova", "fixed": ["33.0.2"], "affected": ">= 33.0.0, <= 33.0.1", "ecosystem": "pypi"}, {"name": "openstack nova", "fixed": ["31.3.1"], "affected": ">= 18.0.0, < 31.3.1", "ecosystem": "vendor"}, {"name": "openstack nova", "fixed": ["32.2.1"], "affected": ">= 32.0.0, < 32.2.1", "ecosystem": "vendor"}, {"name": "openstack nova", "fixed": ["33.0.2"], "affected": ">= 33.0.0, < 33.0.2", "ecosystem": "vendor"}]
ecosystems: ["pypi", "vendor"]
tags: ["cwe-669", "infrastructure", "multi-tenant", "nova", "openstack", "self-hosted"]
not_affected_if: ["single-tenant", "unaffected-version"]
published_at: "2026-06-16T20:16:41+00:00"
first_seen_at: "2026-11-13T00:35:02+00:00"
updated_at: "2026-11-13T00:41:07+00:00"
sources: [{"source": "ghsa", "url": "https://github.com/advisories/GHSA-mfg3-p6m3-gjgr", "first_seen_at": "2026-11-13T00:35:02+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-46448", "first_seen_at": "2026-11-13T00:41:07+00:00"}]
exploit_sources: [{"type": "poc", "url": "https://bugs.launchpad.net/nova/+bug/2151252"}, {"type": "epss", "score": 0.00272, "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-46448"}]
---

# OpenStack Nova: Nova scheduler hint injection bypasses Placement resource claims and scheduling constraints

Link for people: https://infrastack.ai/live/CVE-2026-46448 (this .md is for agents)

Nova's server create API does not strip internal scheduler hints, so an authenticated user can skip Placement resource claims and scheduling constraints such as availability zone, host aggregate and image trait rules. The resulting instance has no Placement allocation, which can exhaust compute node resources and leave cross-tenant data on NVMe devices after deletion.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- pypi:nova affected >= 18.0.0, <= 31.3.0 fixed no fixed version listed
- pypi:nova affected >= 32.0.0, < 32.2.1 fixed 32.2.1
- pypi:nova affected >= 33.0.0, <= 33.0.1 fixed 33.0.2
- vendor:openstack nova affected >= 18.0.0, < 31.3.1 fixed 31.3.1
- vendor:openstack nova affected >= 32.0.0, < 32.2.1 fixed 32.2.1
- vendor:openstack nova affected >= 33.0.0, < 33.0.2 fixed 33.0.2

## How to check

- Check the installed `nova` package version in the Python environment running the Nova API, for example `pip show nova`.
- Compare it against the affected ranges: `>=18.0.0 <31.3.1`, `>=32.0.0 <32.2.1`, `>=33.0.0 <33.0.2`.

## Fix

- `nova` `32.2.1` for the 32.x line
- `nova` `33.0.2` for the 33.x line
- For 18.0.0 through 31.x, the sources give a patched backport at review 993604 for 2025.1 (epoxy) but no explicit fixed version for the 31.x line; the product data lists no fixed version for that range.

## Timeline

- 2026-11-13T00:35:02+00:00 ghsa https://github.com/advisories/GHSA-mfg3-p6m3-gjgr
- 2026-11-13T00:41:07+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-46448

## Documents

- [advisory] Third-party advisory: www.openwall.com https://www.openwall.com/lists/oss-security/2026/06/16/5
- [advisory] Third-party advisory: www.openwall.com http://www.openwall.com/lists/oss-security/2026/06/16/5
- [poc] Exploit: bugs.launchpad.net https://bugs.launchpad.net/nova/+bug/2151252

## From the sources

## Affects

- Nova: >=18.0.0 <31.3.1, >=32.0.0 <32.2.1, >=33.0.0 <33.0.2


## Description
Erichen from the Institute of Computing Technology, Chinese Academy of 
Sciences reported that Nova's server create API does not strip internal 
scheduler hints. An authenticated user can bypass Placement resource 
claims and scheduling constraint enforcement, including availability 
zone, host aggregate, and image trait restrictions. The resulting 
instance has no Placement allocation, which can lead to compute node 
resource exhaustion and cross-tenant data persistence on NVMe devices 
after instance deletion. Deployments running Nova 18.0.0 or later are 
affected.



## Patches

- https://review.opendev.org/993604 (2025.1/epoxy)
- https://review.opendev.org/993603 (2025.2/flamingo)
- https://review.opendev.org/993602 (2026.1/gazpacho)
- https://review.opendev.org/993601 (2026.2/hibiscus)


## Credits
- Erichen from Institute of Computing Technology, Chinese Academy of 
Sciences (CVE-2026-46448)

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