Vulnerability in Canonical Lxd
CVE-2026-34177
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 · last modified .
CVSS v3 metric
CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.006 (47.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 47th percentile — 47.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.006 · change: +0.002
Affected products
- Canonical Lxd — versions 4.12.0, 5.1.0, 6.0.0
Weakness classification (CWE)
References
- github.com/canonical/lxd/security/advisories/GHSA-fm2x-c5qw-4h6f (vendor-advisory, Third Party Advisory, vdb-entry)
- github.com/canonical/lxd/pull/17909 (issue-tracking, patch, Issue Tracking)
Frequently asked questions
- What is CVE-2026-34177?
- CVE-2026-34177 is a critical-severity vulnerability in Canonical Lxd, classified under Incomplete List of Disallowed Inputs. CVSS score: 9.1/10. Published 2026-04-09.
- How severe is CVE-2026-34177?
- Critical severity. CVSS v3 base score is 9.1 out of 10.