Executive brief
Incus, an open-source tool for managing containers and virtual machines, contains a security flaw in how it handles image imports. An authorized user can trick the system into sending network requests to internal or external addresses that should be restricted. This could allow an attacker to map out private internal networks or steal technical details about the server's configuration and version.
Technical details
A blind Server-Side Request Forgery (SSRF) vulnerability exists in the `imgPostURLInfo` function of Incus. The application issues an outbound HTTP HEAD request to a user-supplied URL to resolve image metadata before validating the request against project restrictions (such as `restricted.images.servers`). While the final image download is eventually blocked by policy, the initial HEAD request is executed regardless. These requests include custom headers like `Incus-Server-Architectures` and `Incus-Server-Version`, leaking host environment details. Attackers can leverage this to probe internal services, unroutable address spaces, or cloud metadata endpoints. The issue is fixed in version 7.0.0.
Affected products
- LXC Incus < 7.0.0
Timeline
- 2026-04-30: advisory: GitHub Security Advisory published
- 2026-05-05: disclosed: CVE published to NVD
- 2026-05-05: patched: Fixed in version 7.0.0