High, CVSS 7.0GoPublished
Incus does not verify combined fingerprint when downloading images from simplestreams servers
CVE-2026-33542 · GHSA-p8mm-23gg-jc9r
- Affected
- Go github.com/lxc/incus/v6/client < 6.23.0
- Fixed in
- 6.23.0· Vendor fix available
- Issue
- A lack of validation of the image fingerprint when downloading from simplestreams image servers opens the door to image cache poisoning and under very narrow circumstances exposes other tenants to running attacker controlled images rather than the expected one. Details Incus image fingerprints are computed as the SHA256 of the concatenated image files. When downloading from a public image server using a simplestreams index, Incus requires an HTTPS connection and validates the SHA256 of the individual files but is lacking validation that the concatenated hash of the files matches the fingerprint listed in the simplestreams index. This missing check allows an attacker with access to an Incus environment lacking suitable image source restrictions (restricted.image.server or equivalent firewall rules) to cause Incus to download from an attacker controlled image server which would provide different image files for an other well known image fingerprint. Such an attack can be used…
Recommended action: Upgrade to 6.23.0 or later, then redeploy and verify.A vendor fix does not resolve your finding until you verify it in your own systems.