What is the CVSS score of CVE-2026-34177?

CVE-2026-34177 has a CVSS 3.1 base score of 9.1 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H. EPSS exploitation probability: 0.1%.

Which versions of Canonical are affected by CVE-2026-34177?

CVE-2026-34177 is a critical privilege escalation vulnerability in Canonical LXD versions 4.12-6.7 that allows authenticated users with VM editing permissions to escape project isolation and gain…. A patch is available.

How to fix or mitigate CVE-2026-34177?

Within 24 hours: Identify all LXD deployments running versions 4.12-6.7 and restrict VM instance editing permissions to trusted administrators only. Within 7 days: Apply vendor-released patch to upgrade LXD to version 6.8 or later across all affected clusters. Within 30 days: Conduct access audit to verify no unauthorized privilege escalations occurred, review AppArmor and QEMU configuration logs for injection attempts, and update VM editing RBAC policies to enforce principle of least privilege.

Canonical CVE-2026-34177

EUVD-2026-20872 CRITICAL

Incomplete List of Disallowed Inputs (CWE-184)

2026-04-09 canonical

GHSA-fm2x-c5qw-4h6f

Privilege Escalation Canonical

9.1

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

9.1 CRITICAL

AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

SUSE

CRITICAL

qualitative

Primary rating from NVD.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

High

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Re-analysis Queued

Apr 22, 2026 - 21:07 vuln.today

cvss_changed

EUVD ID Assigned

Apr 09, 2026 - 09:30 euvd

EUVD-2026-20872

Analysis Generated

Apr 09, 2026 - 09:30 vuln.today

Patch released

Apr 09, 2026 - 09:30 nvd

Patch available

CVE Published

Apr 09, 2026 - 09:15 nvd

CRITICAL 9.1

DescriptionCVE.org

Canonical LXD versions 4.12 through 6.7 contain an incomplete denylist in isVMLowLevelOptionForbidden (lxd/project/limits/permissions.go), which omits raw.apparmor and raw.qemu.conf from the set of keys blocked under the restricted.virtual-machines.lowlevel=block project restriction. A remote attacker with can_edit permission on a VM instance in a restricted project can inject an AppArmor rule and a QEMU chardev configuration that bridges the LXD Unix socket into the guest VM, enabling privilege escalation to LXD cluster administrator and subsequently to host root.

AnalysisAI

Privilege escalation in Canonical LXD 4.12-6.7 allows authenticated remote attackers with VM instance editing rights to bypass project restrictions via incomplete denylist validation. Attackers inject AppArmor rules and QEMU chardev configurations through unblocked raw.apparmor and raw.qemu.conf keys, bridging the LXD Unix socket into guest VMs. Successful exploitation enables escalation to LXD cluster administrator and subsequently to host root access. No public exploit identified at time of analysis. Authenticated remote exploitation (PR:H) with cross-scope impact on confidentiality, integrity, and availability.

Technical ContextAI

CWE-184 incomplete denylist vulnerability in isVMLowLevelOptionForbidden function (lxd/project/limits/permissions.go) fails to block raw.apparmor and raw.qemu.conf keys under restricted.virtual-machines.lowlevel=block project restriction. Attackers leverage omitted validation to inject QEMU chardev configurations exposing the LXD management socket to guest VM environments, enabling unauthorized privileged operations.

RemediationAI

Vendor-released patch: Upgrade to Canonical LXD version 6.8 or later, which implements complete denylist validation blocking raw.apparmor and raw.qemu.conf keys in restricted projects. Apply upstream fix available via GitHub pull request https://github.com/canonical/lxd/pull/17909. Review project restriction configurations and audit can_edit permission grants on VM instances in restricted projects. As interim mitigation, revoke can_edit permissions from non-administrative users in projects enforcing restricted.virtual-machines.lowlevel=block until patching completes. Consult vendor security advisory https://github.com/canonical/lxd/security/advisories/GHSA-fm2x-c5qw-4h6f for deployment-specific guidance and validation procedures.