CVE-2026-9639: Nil-pointer dereference in CreateCustomVolumeFromBackup in LXD up to version 6.8 and 5.21 on Linux allows an a

This month

MEDIUM 6.5WATCHLISTUPGRADE

CVE-2026-9639 is a medium-severity flaw (CVSS 6.5) affecting lxd. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Nil-pointer dereference in CreateCustomVolumeFromBackup in LXD up to version 6.8 and 5.21 on Linux allows an authenticated user with can_create_storage_volumes permissions to cause a denial of service via a specially crafted custom-volume backup tarball that omits the expires_at snapshot field.

Why this priority

Public exploit reference
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.5% (top 54%)
CISA exploited list	No
Weakness	CWE-476
Published	2026-06-26
Last modified	2026-10-25

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

Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-26 16:16 UTCPublished CVE record published
2026-10-25 17:10 UTCUpdated Record last modified

canonical lxd UPGRADE

Affected: >= 5.0.0 and < 5.21.5 · >= 6.0 and < 6.9

Fixed in: 5.21.5, 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 5.21.5 (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.

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-2026-9639?

lxd: upgrade to 5.21.5, 6.9. Exact commands for each OS are on this page.

Is CVE-2026-9639 being exploited?

CVE-2026-9639 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-2026-9639 affect?

CVE-2026-9639 affects lxd. Severity is medium (CVSS 6.5). Nil-pointer dereference in CreateCustomVolumeFromBackup in LXD up to version 6.8 and 5.21 on Linux allows an authenticated user with can_create_storage_volumes permissions to cause a denial of service via a specially crafted custom-volume b

How urgent is CVE-2026-9639?

Priority 44/100. Public exploit reference; On your watchlist

Related CVEs

CVE-2026-9640 HIGH 7.2 UPGRADE A privilege escalation vulnerability exists in LXD from 6.0 before 6.9, 5.21.0 before 5.21.5, and 5.0.0 before
CVE-2026-12411 HIGH 8.4 UPGRADE Broken Access Control in the devLXDInstancePatchHandler component of Canonical LXD allows an untrusted guest t
CVE-2026-28385 MEDIUM 5.0 UPGRADE In Canonical LXD versions 4.12 through 6.9, a Server-Side Request Forgery (SSRF) vulnerability in the image im
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-2026-66897 CRITICAL 9.9 UPGRADE A path traversal vulnerability in LXD's instance template processing allows an attacker with container edit pe

References

← Back to latest CVEs