Description

An authorization bypass vulnerability in LXD allows an authenticated attacker to bypass target project restrictions during instance migration. When migrating an instance to a target project, LXD accepts configuration overrides without validating the new configuration against the target project's enforced restrictions. An attacker can exploit this flaw to move instances with disallowed high-privilege configurations into restricted projects, bypassing security controls.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.9",
  "pubDate": "2026-08-12T20:17:47.437Z",
  "pubdate": "2026-08-12T20:17:47.437Z",
  "executiveSummary": "An authorization bypass vulnerability exists within LXD, specifically affecting instance migration mechanisms between projects. The vulnerability is classified as an authorization bypass flaw, enabling authenticated actors to circumvent security boundaries enforced by target projects during the migration phase.\nThe primary impact of this vulnerability is the compromise of multi-tenant or isolated project architectures within LXD deployments. By exploiting this flaw, an attacker can successfully relocate instances configured with disallowed, high-privilege settings into restricted target projects that explicitly prohibit such configurations.\nThe affected system is LXD. The risk implications are severe for environments relying on project-level segmentation to enforce security policies and restrict administrative privileges, as unauthorized privilege escalation and boundary traversal become achievable.\nTo execute this exploit, an attacker requires authentication to the LXD API and must possess the capability to initiate an instance migration process. Exploitation relies on the application accepting configuration overrides during the migration operation without enforcing validation checks against the target project's defined security restrictions and constraints.",
  "technicalDetails": "The root cause of the vulnerability stems from insufficient input validation and authorization enforcement within the LXD instance migration subsystem. Specifically, when an instance is migrated to a target project, the LXD API accepts configuration overrides supplied during the transfer request. The vulnerable component fails to validate these incoming configuration parameters against the security restrictions, limits, and profile constraints enforced by the destination project.\nThe exploitation method involves an authenticated attacker interacting with the LXD REST API to perform an instance migration. The attack flow proceeds as follows: First, the attacker provisions or identifies an instance containing high-privilege configurations, such as privileged container settings or disallowed device mappings, which are permissible in a source project or default context. Second, the attacker initiates a migration request targeting a restricted project. During this API call, configuration overrides are injected or manipulated to bypass project-level restrictions. Third, the LXD daemon processes the migration request, improperly trusts the supplied configuration overrides, and completes the state transfer without validating the resulting instance configuration against the target project's restrictive policies. Finally, the high-privilege instance is successfully instantiated within the restricted project.\nPrerequisites for this attack include authenticated access to the LXD API and the ability to initiate or participate in instance migration workflows. Depending on the environment, network exposure is typically limited to the UNIX socket or the HTTPS REST API exposed by the LXD daemon. Privilege requirements dictate that the attacker must have sufficient authorization to initiate migrations, though the core issue allows them to exceed the boundaries of their assigned project-level privileges.\nThe payload behavior involves passing malicious or restricted configuration parameters within the migration data structures. The post-exploitation impact allows the attacker to operate high-privilege instances within environments designated for restricted workloads, potentially leading to container breakout, host compromise, or unauthorized access to sensitive resources siloed within other projects."
}