CVE-2026-63299: An authorization bypass vulnerability in LXD allows an authenticated user to bypass project-level disk and vol

This month

CRITICAL 9.9UPGRADE

CVE-2026-63299 is a critical-severity flaw (CVSS 9.9) affecting lxd. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An authorization bypass vulnerability in LXD allows an authenticated user to bypass project-level disk and volume limits. Two related code paths fail to verify resource limits during volume operations: the storagePoolVolumeTypePostMove function omits the limits.AllowVolumeCreation check before moving a volume across projects, and volume snapshot restore operations skip the AllowVolumeUpdate check when the configuration is nil (Config == nil). An

Why this priority

Critical severity
Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	9.9 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.6% (top 53%)
CISA exploited list	No
Weakness	CWE-770
Published	2026-08-12
Last modified	2026-10-23

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

Am I affected?

Timeline

2026-08-12 20:17 UTCPublished CVE record published
2026-10-23 19:10 UTCUpdated Record last modified

canonical lxd UPGRADE

Affected: >= 5.0.0 and < 5.0.8 · >= 5.1 and < 5.21.6 · >= 6.0 and < 6.10

Fixed in: 5.0.8, 5.21.6, 6.10

Safe to downgrade to: a release before 5.0.0

1. Check installed version

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

2. UPGRADE to 5.0.8 (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 5.0.0 (Debian / Ubuntu)

apt-cache madison lxd sudo apt install lxd=<VERSION_BEFORE_5.0.0> 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_5.0.0> 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.

Exact fixes by distribution

Fedora 46 · rubygem-eventmachine · FIXED · 1.2.7-37.fc46 · FEDORA-2026-7194c202a2 · source

sudo dnf upgrade --advisory=FEDORA-2026-7194c202a2

Debian 12 · lxd · NO FIX YET

Debian 13 · lxd · NO FIX YET

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Write-up: github.com/canonical/lxd/security/advisories/GHSA-5h78-p252-989h

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.

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References

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