CVE-2026-34177: Canonical LXD versions 4.12 through 6.7 contain an incomplete denylist in isVMLowLevelOptionForbidden (lxd/pro

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CRITICAL 9.1UPGRADE

CVE-2026-34177 is a critical-severity flaw (CVSS 9.1) affecting lxd. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

Critical severity

A fixed release or distro patch exists.

Risk facts

CVSS score	9.1 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	High
User interaction	None
EPSS exploit chance	0.4% (top 70%)
CISA exploited list	No
Weakness	CWE-184
Published	2026-04-09
Last modified	2026-10-26

Publisher (CNA): Canonical Ltd. · Vendor: canonical

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-09 10:16 UTCPublished CVE record published
2026-10-26 21:10 UTCUpdated Record last modified

canonical lxd UPGRADE

Affected: >= 4.12 and <= 5.0.6 · >= 5.21.0 and <= 5.21.4 · >= 6.0 and <= 6.7

Fixed in: newer than 6.7

Safe to downgrade to: a release before 4.12

1. Check installed version

apt-cache policy lxd || rpm -q lxd || lxd --version

2. UPGRADE to newer than 6.7 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade lxd

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade lxd

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 4.12 (Debian / Ubuntu)

apt-cache madison lxd sudo apt install lxd=<VERSION_BEFORE_4.12> sudo apt-mark hold lxd

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list lxd sudo dnf downgrade lxd-<VERSION_BEFORE_4.12> sudo dnf versionlock add lxd

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-34177?

lxd: upgrade to newer than 6.7. Exact commands for each OS are on this page.

Is CVE-2026-34177 being exploited?

CVE-2026-34177 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-34177 affect?

CVE-2026-34177 affects lxd. Severity is critical (CVSS 9.1). 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-

How urgent is CVE-2026-34177?

Priority 39/100. Critical severity

Software pages

QEMU vulnerabilities

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References

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