CVE-2026-34177: CWE-184 Incomplete list of disallowed inputs in Canonical lxd
Canonical LXD versions 4. 12 through 6. 7 have a vulnerability due to an incomplete denylist in the isVMLowLevelOptionForbidden function. This omission allows a remote attacker with can_edit permission on a VM instance in a restricted project to inject AppArmor rules and QEMU chardev configurations. Exploiting this can lead to privilege escalation to LXD cluster administrator and potentially host root. The vulnerability is tracked as CVE-2026-34177 with a critical severity score of 9. 1. No official patch or remediation guidance has been provided yet.
AI Analysis
Technical Summary
CVE-2026-34177 is a critical vulnerability in Canonical LXD (versions 4.12 through 6.7) caused by an incomplete denylist in the isVMLowLevelOptionForbidden function (lxd/project/limits/permissions.go). The denylist fails to block the keys raw.apparmor and raw.qemu.conf under the restricted.virtual-machines.lowlevel=block project restriction. This allows a remote attacker with can_edit permission on a VM instance within a restricted project to inject malicious AppArmor rules and QEMU chardev configurations. Such injection can bridge the LXD Unix socket into the guest VM, enabling privilege escalation first to LXD cluster administrator and then to host root privileges.
Potential Impact
An attacker with can_edit permission on a VM instance in a restricted project can escalate privileges to LXD cluster administrator and subsequently to host root. This compromises the confidentiality, integrity, and availability of the host system and all VMs managed by the LXD cluster. The CVSS v3.1 score is 9.1 (critical), reflecting network attack vector, low attack complexity, high privileges required, no user interaction, and complete impact on confidentiality, integrity, and availability.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is released, restrict can_edit permissions carefully and monitor for suspicious activity related to VM configuration changes. Avoid granting can_edit permissions to untrusted users in restricted projects. Follow updates from Canonical for official patches or temporary mitigations.
CVE-2026-34177: CWE-184 Incomplete list of disallowed inputs in Canonical lxd
Description
Canonical LXD versions 4. 12 through 6. 7 have a vulnerability due to an incomplete denylist in the isVMLowLevelOptionForbidden function. This omission allows a remote attacker with can_edit permission on a VM instance in a restricted project to inject AppArmor rules and QEMU chardev configurations. Exploiting this can lead to privilege escalation to LXD cluster administrator and potentially host root. The vulnerability is tracked as CVE-2026-34177 with a critical severity score of 9. 1. No official patch or remediation guidance has been provided yet.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-34177 is a critical vulnerability in Canonical LXD (versions 4.12 through 6.7) caused by an incomplete denylist in the isVMLowLevelOptionForbidden function (lxd/project/limits/permissions.go). The denylist fails to block the keys raw.apparmor and raw.qemu.conf under the restricted.virtual-machines.lowlevel=block project restriction. This allows a remote attacker with can_edit permission on a VM instance within a restricted project to inject malicious AppArmor rules and QEMU chardev configurations. Such injection can bridge the LXD Unix socket into the guest VM, enabling privilege escalation first to LXD cluster administrator and then to host root privileges.
Potential Impact
An attacker with can_edit permission on a VM instance in a restricted project can escalate privileges to LXD cluster administrator and subsequently to host root. This compromises the confidentiality, integrity, and availability of the host system and all VMs managed by the LXD cluster. The CVSS v3.1 score is 9.1 (critical), reflecting network attack vector, low attack complexity, high privileges required, no user interaction, and complete impact on confidentiality, integrity, and availability.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is released, restrict can_edit permissions carefully and monitor for suspicious activity related to VM configuration changes. Avoid granting can_edit permissions to untrusted users in restricted projects. Follow updates from Canonical for official patches or temporary mitigations.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- canonical
- Date Reserved
- 2026-03-26T09:24:08.448Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69d773081cc7ad14da8bdc1b
Added to database: 4/9/2026, 9:36:08 AM
Last enriched: 4/16/2026, 12:25:18 PM
Last updated: 5/24/2026, 11:19:48 AM
Views: 167
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