CVE-2026-34178 Importing a crafted backup leads to project restriction bypass
Authenticated attackers can bypass LXD project restrictions by crafting backup archives, enabling privileged container creation and host compromise.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-34178?
CVE-2026-34178 is a critical vulnerability in Canonical lxd, published on 9 Apr 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Official description
In Canonical LXD before 6.8, the backup import path validates project restrictions against backup/index.yaml in the supplied tar archive but creates the instance from backup/container/backup.yaml, a separate file in the same archive that is never checked against project restrictions. An authenticated remote attacker with instance-creation permission in a restricted project can craft a backup archive where backup.yaml carries restricted settings such as security.privileged=true or raw.lxc directives, bypassing all project restriction enforcement and allowing full host compromise.
Weakness: CWE-20
Which versions are affected by CVE-2026-34178?
3 open source packages ship an affected version, including github.com/canonical/lxd. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/canonical/lxd Go | From 0.0.0-20210305023314-538ac3df036e | None |
github.com/canonical/lxd Go | From 0.0.0-20210305023314-538ac3df036e to 0.0.0-20260226085519-736f34afb267 | None |
github.com/canonical/lxd Go | From 0.0.0-20210305023314-538ac3df036e to 0.0.0-20260226085519-736f34afb267 | None |
Products include Canonical Lxd.
How do I fix CVE-2026-34178?
Upgrade to a fixed version.
Is CVE-2026-34178 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34178 exists.
Other vulnerabilities in Canonical lxd
- CVE-2026-66897 Instance template path traversal allows arbitrary host file write as root
- CVE-2026-62420 Cross-project cluster migration bypasses project restrictions via cluster notification flag
- CVE-2026-63293 Arbitrary File Read/Write: metadata.yaml symlink in image allows host filesystem access as root
- CVE-2026-63294 Root RCE via image backup.yaml symlink
- CVE-2026-63296 Project restriction bypass via instance migration config override
Sources
Also known as DEBIAN-CVE-2026-34178, GHSA-q96j-3fmm-7fv4, GO-2026-5576, UBUNTU-CVE-2026-34178.