LXD 4.0.11 release notes

This is a LTS release and is recommended for production use.

Release notes content

These release notes cover updates in the core LXD repository and the LXD snap package.

Highlights

Ubuntu Pro detection

LXD now detects whether the host system is attached to Ubuntu Pro and advertises this as a feature in the user agent string. This allows LXD to expose Pro-specific capabilities when running on a Pro-attached host.

Bug fixes

The following bug fixes are included in this release.

• Arbitrary file write on host via exec-output symlink in crafted image (CVE-2026-48750)

• Arbitrary file read+write on host via templates/ symlink in malicious image (CVE-2026-48752)

• Arbitrary file read+write on host via rootfs/ symlink in malicious image (CVE-2026-48749)

• Argument injection in backup compression algorithm leading to AFW and ACE (CVE-2026-48755)

• Arbitrary file write on client due to trusted image hash (CVE-2026-48769)

• Panic when importing backup configs that contain nil slices (CVE-2026-40197)

• Template sandbox escapes and crash risks in pongo2 rendering (CVE-2026-33897)

• Overly permissive storage pool volume directory permissions expose instance data (CVE-2025-64507)

• Potential shell expansion in LXC hook arguments due to incorrect quoting

• Improve validation when editing certificates to reject invalid or inconsistent configurations

• Add raw.apparmor and raw.qemu.conf to the list of forbidden low-level options when low-level configuration is restricted in project limits

• Fail fast when an unsupported compression algorithm is specified for backup or image operations

• Fix panics when importing backups with missing or invalid configuration data

• Fix AppArmor rules for unprivileged containers to allow devpts, procfs, and sysfs mounts

Backwards-incompatible changes

These changes are not compatible with older versions of LXD or its clients.

Secure Boot compatibility limitations (Microsoft 2023 CA rotation)

LXD 4.0 LTS bundles Microsoft UEFI 2011 CAs that expired in June 2026. Because LXD 4.0 LTS is out of standard support and ships an older EDK2 firmware utilizing a legacy 2MB flash layout, it will not receive updates to support the new Microsoft 2023 CAs. Due to this 2MB firmware size constraint, LXD 4.0 LTS already has limited compatibility with modern guests that require Secure Boot.

Implications: Virtual machine images using a boot loader signed exclusively with the 2023 CA will fail Secure Boot validation and refuse to boot.

Workaround: Secure Boot enforcement might need to be disabled for the instance:

lxc config set <instance_name> security.secureboot false

Minimum system requirement changes

The minimum supported version of some components has changed:

• The minimum required version of Go to build LXD is now 1.18 (see Updated minimum Go version).

Updated minimum Go version

If you are building LXD from source instead of using a package manager, the minimum version of Go required to build LXD is now 1.18.

Change log

View the complete list of all changes in this release.

Downloads

The source tarballs and binary clients can be found on our download page.

Binary packages are also available for:

• Linux: snap install lxd --channel=4.0/stable

• MacOS client: brew install lxc

• Windows client: choco install lxc