CVE-2026-63297: An authorization bypass vulnerability in LXD due to a timing flaw during configuration merging allows an authe

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CRITICAL 9.9UPGRADE

CVE-2026-63297 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 due to a timing flaw during configuration merging allows an authenticated attacker to bypass target project restrictions during cross-project instance copies. When copying an instance to a target project, LXD performs restriction checks before configuration merging is complete, creating a time-of-check to time-of-use (TOCTOU) condition. An attacker can exploit this flaw to copy instances with disallowe

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	0.3% (top 73%)
CISA exploited list	No
Weakness	CWE-367, CWE-863
Published	2026-08-12
Last modified	2026-10-23

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

Last updated 2026-10-23 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

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 < 6.9

Fixed in: 5.0.8, 5.21.6, 6.9

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 · kwin-zones · FIXED · 1.0.13-1.fc46 · FEDORA-2026-95888f332b · source

sudo dnf upgrade --advisory=FEDORA-2026-95888f332b

Fedora ELN · nginx-mod-brotli · FIXED · 1.0.0~rc-16.eln159 · FEDORA-2026-501a6a8273 · source

sudo dnf upgrade --advisory=FEDORA-2026-501a6a8273

Debian 12 · lxd · NO FIX YET

Debian 13 · lxd · NO FIX YET

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-2026-63297?

lxd: upgrade to 5.0.8, 5.21.6, 6.9. Exact commands for each OS are on this page.

Is CVE-2026-63297 being exploited?

CVE-2026-63297 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-2026-63297 affect?

CVE-2026-63297 affects lxd. Severity is critical (CVSS 9.9). An authorization bypass vulnerability in LXD due to a timing flaw during configuration merging allows an authenticated attacker to bypass target project restrictions during cross-project instance copies. When copying an instance to a target

How urgent is CVE-2026-63297?

Priority 46/100. Critical severity; Public exploit reference

Related CVEs

CVE-2026-66897 CRITICAL 9.9 UPGRADE A path traversal vulnerability in LXD's instance template processing allows an attacker with container edit pe
CVE-2025-54289 HIGH 8.1 UPGRADE Privilege Escalation in operations API in Canonical LXD <6.5 on multiple platforms allows attacker with read p
CVE-2026-63294 CRITICAL 9.9 UPGRADE A link following vulnerability in LXD allows an attacker to achieve root command execution on the host system
CVE-2026-63298 CRITICAL 9.9 UPGRADE An improper neutralization of special elements vulnerability in LXD's NVIDIA instance configuration handling a
CVE-2026-63293 CRITICAL 9.9 UPGRADE A link following vulnerability in LXD allows an attacker to achieve arbitrary file read and write operations o

References

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