Project restriction `restricted.containers.privilege=isolated` bypassable by omitting `security.idmap.isolated` (CVE-2026-63295) | HOL Guard CVE

Medium · CVSS 4.3CVE-2026-63295

Project restriction `restricted.containers.privilege=isolated` bypassable by omitting `security.idmap.isolated`

Answer in brief

CVE-2026-63295 records a Medium severity (CVSS 4.3) vulnerability in Project restriction `restricted.containers.privilege=isolated` bypassable by omitting `security.idmap.isolated`. 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 29, 2026First seen by HOL Aug 12, 2026Material review Sep 11, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 4.3
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 4.3. 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	>=4.0.0 <4.0.12 \|\| >=5.0.0 <5.0.8 \|\| >=5.21.0 <5.21.6 \|\| >=6.0 <6.10	4.0.12, 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 4.0.12 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

GitHub security advisorygithub.com

Upstream source description

An authorization bypass vulnerability in LXD allows an authenticated attacker to bypass project-level container isolation restrictions. When a project is configured with restrictions on container privileges (such as enforcing restricted.containers.privilege=isolated), LXD fails to enforce the requirement if an instance configuration omits the security.idmap.isolated key. An attacker can exploit this flaw by creating or updating an instance without explicitly setting security.idmap.isolated, bypassing the target project's security constraints.

Quoted source text, attributed separately from HOL analysis.