VM lowlevel restriction bypass via raw.apparmor and raw.qemu.conf_CVE-2026-34177

9.1 / 10

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

Description

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.

Basic Information

ID CVE-2026-34177

Source canonical

Published Apr 9, 2026 at 09:15

Modified Apr 9, 2026 at 12:12

Affected Product

Vendor Canonical

Product lxd

Version 4.12.0

Affected Versions Canonical lxd 4.12.0
Canonical lxd 5.1.0
Canonical lxd 6.0.0

CWE Classification

CWE-184

References

{
    "lastseen": "",
    "description": "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.",
    "published": "2026-04-09T09:15:27.532Z",
    "modified": "2026-04-09T12:12:48.251Z",
    "type": "cve",
    "title": "VM lowlevel restriction bypass via raw.apparmor and raw.qemu.conf",
    "source": "canonical",
    "references": "https://github.com/canonical/lxd/security/advisories/GHSA-fm2x-c5qw-4h6f\nhttps://github.com/canonical/lxd/pull/17909",
    "id": "CVE-2026-34177",
    "bulletinFamily": "",
    "cwe": [
        "CWE-184"
    ],
    "cvelist": null,
    "sourceData": "Canonical lxd 4.12.0\nCanonical lxd 5.1.0\nCanonical lxd 6.0.0",
    "sourceHref": "",
    "cvss": {
        "score": 9.1,
        "severity": "CRITICAL",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "lxd",
    "version": "4.12.0",
    "vendor": "Canonical",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}