# CVE-2026-63300: Cross-project instance move bypasses all project restrictions allowing host command execution

> Authenticated attackers can bypass project restrictions by moving instances, enabling host command execution in restricted LXD environments.

- **Severity:** Critical 9.9 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Aug 2026
- **Updated:** 13 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-63300, GHSA-5g5r-wh97-qcq2, UBUNTU-CVE-2026-63300

## What is CVE-2026-63300?

CVE-2026-63300 is a critical missing authorization vulnerability in Canonical LXD, published on 12 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

An improper validation vulnerability in the instancePostMigration function in lxd/instance_post.go of LXD allows an authenticated attacker with can_create_instances permissions on a restricted project to bypass project-level security restrictions. When migrating an instance between projects, LXD fails to validate the instance's configuration against the target project's enforced restrictions (such as restricted.containers.lowlevel, restricted.devices.*, and restricted.networks.access). An attacker can exploit this by creating a disallowed or high-privilege instance in an unrestricted project and subsequently moving it into the restricted project.

Weakness: CWE-862 (Missing Authorization)

## Which versions are affected by CVE-2026-63300?

It affects 1 product.


Products: Canonical Lxd.

## How do I fix CVE-2026-63300?

No fix has been published for CVE-2026-63300 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-63300 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-63300 exists.

## Other vulnerabilities in Canonical LXD

- [CVE-2026-66897](https://insights.sbomify.com/CVE-2026-66897/): Instance template path traversal allows arbitrary host file write as root (critical 9.9)
- [CVE-2026-62420](https://insights.sbomify.com/CVE-2026-62420/): Cross-project cluster migration bypasses project restrictions via cluster notification flag (critical 9.9)
- [CVE-2026-63293](https://insights.sbomify.com/CVE-2026-63293/): Arbitrary File Read/Write: metadata.yaml symlink in image allows host filesystem access as root (critical 9.9)
- [CVE-2026-63294](https://insights.sbomify.com/CVE-2026-63294/): Root RCE via image backup.yaml symlink (critical 9.9)
- [CVE-2026-63296](https://insights.sbomify.com/CVE-2026-63296/): Project restriction bypass via instance migration config override (critical 9.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-63300 and fix it if it is affected.

What it is: CVE-2026-63300 is a critical missing authorization vulnerability in Canonical LXD, published on 12 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-63300 exists.

Affected product: Canonical LXD. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-63300/ (Markdown: https://insights.sbomify.com/CVE-2026-63300/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-63300
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-63300
- OSV: https://osv.dev/vulnerability/CVE-2026-63300

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-63300/
Summaries are generated and may contain mistakes; the official description above is the record.