Path Traversal in Linuxcontainers Incus
CVE-2026-33945
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.
Vulnerability class: Path Traversal (Directory Traversal)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.9 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.005 (42.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 42nd percentile — 42.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.005 · change: +0.001
Affected products
- Linuxcontainers Incus
- Lxc Incus — versions < 6.23.0
Weakness classification (CWE)
References
- github.com/lxc/incus/security/advisories/GHSA-q4q8-7f2j-9h9f (Vendor Advisory)
Frequently asked questions
- What is CVE-2026-33945?
- CVE-2026-33945 is a critical-severity vulnerability in Linuxcontainers Incus, classified under Path Traversal. CVSS score: 9.9/10. Published 2026-03-27.
- How severe is CVE-2026-33945?
- Critical severity. CVSS v3 base score is 9.9 out of 10.