CVE-2026-33542 Incus does not verify combined fingerprint when downloading images from simplestreams servers

What is CVE-2026-33542?

CVE-2026-33542 is a medium-severity vulnerability in lxc incus, published on 26 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

Incus is a system container and virtual machine manager. Prior to version 6.23.0, 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. Version 6.23.0 patches the issue.

Weakness: CWE-295

Which versions are affected by CVE-2026-33542?

4 open source packages ship an affected version, including github.com/lxc/incus/v6/client, github.com/lxc/incus and github.com/lxc/incus/v6. It affects 1 product.

Products include Linuxcontainers Incus.

How do I fix CVE-2026-33542?

Upgrade github.com/lxc/incus/v6/client to 6.23.0 or later.

Is CVE-2026-33542 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-33542 exists.

Other vulnerabilities in lxc incus

• CVE-2026-33897 Incus vulnerable to arbitrary file read and write through pongo templates Critical 10.0
• CVE-2026-33945 Abitrary file write through systemd-creds option Critical 10.0
• CVE-2026-33898 Local Incus UI web server vulnerable to nuthentication bypass High 8.8
• CVE-2026-23953 Incus container environment configuration newline injection High 8.7
• CVE-2026-23954 Incus container image templating arbitrary host file read and write High 8.7

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2026-33542, GHSA-p8mm-23gg-jc9r, GO-2026-4882, UBUNTU-CVE-2026-33542.