Vulnerability · Published Mar 26, 2026 · Assigned by GitHub_M
CVE-2026-33945Abitrary file write through systemd-creds option
Critical 10.0
In plain English
A critical-severity path traversal in incus from lxc. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 40% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Incus is a system container and virtual machine manager. Incus instances have an option to provide credentials to systemd in the guest. For containers, this is handled through a shared directory. Prior to version 6.23.0, an attacker can set a configuration key named something like `systemd.credential.../../../../../../root/.bashrc` to cause Incus to write outside of the `credentials` directory associated with the container. This makes use of the fact that the Incus syntax for such credentials is `systemd.credential.XYZ` where `XYZ` can itself contain more periods. While it's not possible to read any data this way, it's possible to write to arbitrary files as root, enabling both privilege escalation and denial of service attacks. Version 6.23.0 fixes the issue.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:14 | incus | 6.0.6-2 | DEBIAN-CVE-2026-33945 |
| Go | github.com/lxc/incus | no fix listed | GO-2026-4884 |
| Go | github.com/lxc/incus/v6 | 6.23.0 | GO-2026-4884 |
| Go | github.com/lxc/incus/v6 | 6.23.0 | GHSA-q4q8-7f2j-9h9f |
| Ubuntu:25.10 | incus | no fix listed | UBUNTU-CVE-2026-33945 |
| Ubuntu:26.10 | incus | no fix listed | UBUNTU-CVE-2026-33945 |
Affected products (as reported)
Weakness: CWE-22 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
References
- https://github.com/lxc/incus/security/advisories/GHSA-q4q8-7f2j-9h9f x_refsource_CONFIRM