Cross-project instance move bypasses all project restrictions allowing host command execution (CVE-2026-63300) | HOL Guard CVE

Critical · CVSS 9.9CVE-2026-63300

Cross-project instance move bypasses all project restrictions allowing host command execution

Answer in brief

CVE-2026-63300 records a Critical severity (CVSS 9.9) vulnerability in Cross-project instance move bypasses all project restrictions allowing host command execution. The current sources do not mark it as known exploited. The current feed maps Canonical/LXD (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 12, 2026Updated Sep 11, 2026Source checked Sep 27, 2026First seen by HOL Aug 12, 2026Material review Sep 11, 2026

Upstream Advisory

Key facts

Risk: Critical · CVSS 9.9
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 9.9. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Canonical/LXD (generic). Check affected ranges and fixed versions before updating.

Affected products and reported versions
Product	Affected versions	Fixed versions
cpe:2.3:a:canonical:lxd::::::::	Not reported	Not reported

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Canonical/LXDgeneric	>=5.0.0 <5.0.8 \|\| >=5.21.0 <5.21.6 \|\| >=6.0 <6.10	5.0.8, 5.21.6, 6.10

Recommended response

Check inventory. Check lockfiles and deployed manifests for Canonical/LXD.
Review the reported fix. Update Canonical/LXD to 5.0.8 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 12, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 12, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.