NULL pointer dereference in LXD - CVE-2026-9639
Published: June 29, 2026
Vulnerability identifier: #VU135805
CSH Severity: Low
CVSS v4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-9639
CWE-ID: CWE-476
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to a null pointer dereference in CreateCustomVolumeFromBackup in lxd/storage/backend_lxd.go when importing a crafted custom-volume backup tarball with an omitted volumes[0].snapshots[*].expires_at field. A remote user can upload a specially crafted backup tarball to cause a denial of service.
The issue crashes the entire lxd daemon process while handling a custom storage volume import request.
Affected software
LXD
Debian Linux
lxd (Debian package)
Debian Linux
lxd (Debian package)
How to mitigate CVE-2026-9639
Install security update from vendor's website.
LXD - addressed in versions 5.21.5, 6.9
lxd (Debian package) - update to 5.0.2+git20231211.1364ae4-9+deb13u7
lxd (Debian package) - update to 5.0.2+git20231211.1364ae4-9+deb13u7