Description

Incus is a system container and virtual machine manager. Prior to version 7.3.0, when migrating an instance to another cluster member, user-supplied configuration overrides (including security-critical keys like `security.privileged` and `raw.lxc`) are applied without any project restriction enforcement, allowing a restricted project user to escalate to a privileged container and escape to the host. Version 7.3.0 patches the issue.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.9",
  "pubDate": "2026-08-21T15:16:46.147Z",
  "pubdate": "2026-08-21T15:16:46.147Z",
  "executiveSummary": "A privilege escalation vulnerability exists in Incus prior to version 7.3.0 within the cluster instance migration mechanism. The vulnerability stems from the improper handling of user-supplied configuration overrides during the migration of an instance to another cluster member.\nSpecifically, security-critical keys such as security.privileged and raw.lxc are applied without enforcing proper project restrictions. This allows a restricted project user to manipulate instance configurations during migration operations.\nThe impact of this vulnerability is severe, enabling a malicious user with access to a restricted project to provision and execute a privileged container. From a privileged container context, an attacker can achieve container escape, ultimately leading to arbitrary code execution and full compromise of the underlying host operating system.\nThe vulnerability affects Incus systems prior to version 7.3.0. Exploitation requires authenticated access to a restricted project within a clustered Incus deployment and the ability to initiate instance migration. Risk implications include complete host compromise and bypass of multi-tenant project isolation boundaries within cluster environments.",
  "technicalDetails": "The vulnerability resides in the cluster instance migration subsystem of Incus, specifically in how configuration overrides supplied by users are validated and processed when an instance is moved between cluster members.\nThe root cause is the absence of project restriction enforcement when applying incoming configuration overrides during migration. Normally, security-sensitive configuration keys are restricted to prevent non-privileged users from defining configurations that undermine host security.\nDuring migration, user-supplied configuration overrides—including critical keys such as security.privileged and raw.lxc—bypass these validation checks and are successfully applied to the target instance on the destination cluster member.\nThe attack flow proceeds as follows: 1) An attacker with access to a restricted project initiates the migration of an instance to another cluster member. 2) During the migration request, the attacker supplies malicious configuration overrides containing security-critical keys like security.privileged=true or arbitrary raw.lxc directives. 3) The target cluster member processes the migration payload and applies the unvalidated configuration overrides without verifying if the originating project context permits such settings. 4) The instance is instantiated with privileged parameters on the destination host. 5) Once the attacker executes commands inside the newly privileged container, standard container isolation boundaries are removed, allowing the attacker to perform a container escape and gain administrative access to the underlying host operating system.\nThe affected component is the instance migration handler within Incus prior to version 7.3.0. Exploitation requires authentication within a restricted project context, but does not require administrative privileges at the global Incus daemon level.\nPost-exploitation impact includes full system compromise of the cluster host, potential lateral movement across the cluster infrastructure, and total loss of confidentiality, integrity, and availability for the affected cluster nodes."
}