Incus blind SSRF via image import preflight HEAD request

Summary

Incus is an open source container and virtual machine manager. In versions prior to 7.0.0, the image import flow issues an outbound HEAD request to a user-supplied URL before validating the request against project restrictions such as restricted.images.servers. The imgPostURLInfo function constructs and sends a HEAD request directly from the attacker-supplied source URL to resolve image metadata, and this network interaction occurs before the flow reaches the point where the import would be rejected by policy. Although the actual image download is blocked by the project restriction, an authenticated user can coerce the daemon into making blind HEAD requests to arbitrary destinations. These requests include server metadata in custom headers (Incus-Server-Architectures, Incus-Server-Version), which discloses information about the host environment to the attacker-controlled endpoint. This blind SSRF primitive can be used to probe internal services, unroutable address space, or cloud metadata endpoints reachable from the host. This vulnerability pattern is similar to CVE-2026-24767. This issue has been fixed in version 7.0.0.

Timeline

1. May 5, 2026, 7:56 PM UTCCVE published
2. May 6, 2026, 2:50 PM UTCCISA SSVC assessment

   Exploitation: poc · Automatable: no · Technical impact: partial

3. May 6, 2026, 3:24 PM UTCRecord last updated

Affected versions

• lxc incus

  fixed in 7.0.0

• github.com/lxc/incusGo

  All versions

• github.com/lxc/incus/v6Go

  All versions

• github.com/lxc/incus/v7Go

  fixed in 7.0.0

• github.com/lxc/incus/v6/cmd/incusdGo

  fixed in 7.0.0

References 2