9.1

CVE-2026-34177: canonical lxd Incomplete List of Disallowed Inputs

CVSS: 9.1v3.1CriticalAnalyzed
AliasesUBUNTU-CVE-2026-34177DEBIAN-CVE-2026-34177GHSA-fm2x-c5qw-4h6f
Published 09-04-2026Last modified 09-04-2026
Open JSON

Vulnerability summary

CVE-2026-34177 is a critical (CVSS 9.1) Incomplete List of Disallowed Inputs vulnerability in canonical lxd. EPSS estimates a 0.61% chance of exploitation in the next 30 days, higher than 48.2% of scored vulnerabilities.

Overall risk
70/100
0100
High · default modelHow is this calculated?
CVSS score
9.1/10
010
Critical · v3.1 (CVE.org)
EPSS score
0.61%
0%100%
Low · +0.25 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 2 · Related 2
OPENSUSE-SU-2026:21761-1SUSE-SU-2026:23625-1

Timeline

  1. 09-04-2026
    PublishedVulnerability first disclosed.
  2. 09-04-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

0.61%

Chance of exploitation in the next 30 days

Percentile

48%

Versus all other CVEs

30-day change

+0.25 pp

From 0.36% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.61%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Debian2 products
  • incus< 6.0.2-1
  • lxdAll versions (No fix recorded) | < 5.0.2+git20231211.1364ae4-9+deb13u5
Canonical1 product
  • lxd≥ 4.12.0, < 5.0.7 | ≥ 5.1.0, < 5.21.5 | ≥ 6.0.0, < 6.8.0 | ≥ 4.12, ≤ 5.0.6 | ≥ 5.21.0, ≤ 5.21.4 | ≥ 6.0, ≤ 6.7
Github.com/canonical1 product
  • lxd≥ 0.0.0-20210305023314-538ac3df036e, ≤ 0.0.0-20260226085519-736f34afb267 | ≥ 0.0.0-20210305023314-538ac3df036e (No fix recorded)
Ubuntu1 product
  • incusAll versions (No fix recorded)

4 vendors · 5 products

References

7 links