CVE-2026-33897 Incus vulnerable to arbitrary file read and write through pongo templates
Attackers can exploit pongo2 templates to bypass chroot isolation, enabling arbitrary file read and write as root on the host system.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-33897?
CVE-2026-33897 is a critical path traversal 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, instance template files can be used to cause arbitrary read or writes as root on the host server. Incus allows for pongo2 templates within instances which can be used at various times in the instance lifecycle to template files inside of the instance. This particular implementation of pongo2 within Incus allowed for file read/write but with the expectation that the pongo2 chroot feature would isolate all such access to the instance's filesystem. This was allowed such that a template could theoretically read a file and then generate a new version of said file. Unfortunately the chroot isolation mechanism is entirely skipped by pongo2 leading to easy access to the entire system's filesystem with root privileges. Version 6.23.0 patches the issue.
Weakness: CWE-1336
Which versions are affected by CVE-2026-33897?
6 open source packages ship an affected version, including github.com/lxc/incus and github.com/lxc/incus/v6. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/lxc/incus Go | All versions | None |
github.com/lxc/incus Go | All versions to 0.7.0 | None |
github.com/lxc/incus Go | All versions to 0.7.0 | None |
github.com/lxc/incus/v6 Go | All versions | 6.23.0 |
github.com/lxc/incus/v6 Go | All versions | 6.23.0 |
github.com/lxc/incus/v6 Go | All versions | 6.23.0 |
Products include Linuxcontainers Incus.
How do I fix CVE-2026-33897?
Upgrade to a fixed version.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-33897 being exploited?
There is no known exploitation of CVE-2026-33897 in the wild and no public exploit code.
Other vulnerabilities in lxc incus
- CVE-2026-33945 Abitrary file write through systemd-creds option
- CVE-2026-33898 Local Incus UI web server vulnerable to nuthentication bypass
- CVE-2026-23953 Incus container environment configuration newline injection
- CVE-2026-23954 Incus container image templating arbitrary host file read and write
- CVE-2025-64507 Incus vulnerable to local privilege escalation through custom storage volumes
Sources
Also known as DEBIAN-CVE-2026-33897, GHSA-83xr-5xxr-mh92, GO-2026-4881, UBUNTU-CVE-2026-33897.