CVE-2026-66898: A path traversal vulnerability in LXD allows an attacker to manipulate file system paths during backup import

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CRITICAL 9.9UPGRADE

CVE-2026-66898 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.

A path traversal vulnerability in LXD allows an attacker to manipulate file system paths during backup import and restore operations. When importing or restoring a backup archive, LXD fails to validate instance and storage volume names contained within the archive metadata. An attacker can exploit this flaw by supplying a crafted backup archive with malicious instance or volume names containing path traversal sequences, potentially allowing file

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 52%)
CISA exploited list	No
Weakness	CWE-22
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 21:17 UTCPublished CVE record published
2026-10-23 19:10 UTCUpdated Record last modified

canonical lxd UPGRADE

Affected: >= 4.0.0 and < 4.0.12 · >= 5.0.0 and < 5.0.4 · >= 5.1 and < 5.21.2 · 6.0

Fixed in: 4.0.12, 5.0.4, 5.21.2

Safe to downgrade to: a release before 4.0.0

1. Check installed version

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

2. UPGRADE to 4.0.12 (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 4.0.0 (Debian / Ubuntu)

apt-cache madison lxd sudo apt install lxd=<VERSION_BEFORE_4.0.0> 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_4.0.0> 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-m857-c7gc-c984

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-2026-66898?

lxd: upgrade to 4.0.12, 5.0.4, 5.21.2. Exact commands for each OS are on this page.

Is CVE-2026-66898 being exploited?

CVE-2026-66898 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-2026-66898 affect?

CVE-2026-66898 affects lxd. Severity is critical (CVSS 9.9). A path traversal vulnerability in LXD allows an attacker to manipulate file system paths during backup import and restore operations. When importing or restoring a backup archive, LXD fails to validate instance and storage volume names cont

How urgent is CVE-2026-66898?

Priority 52/100. 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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