Vulnerability Description
Incus is a system container and virtual machine manager. Incus provides an API to retrieve VM screenshots. That API relies on the use of a temporary file for QEMU to write the screenshot to which is then picked up and sent to the user prior to deletion. As versions prior to 6.23.0 use predictable paths under /tmp for this, an attacker with local access to the system can abuse this mechanism by creating their own symlinks ahead of time. On the vast majority of Linux systems, this will result in a "Permission denied" error when requesting a screenshot. That's because the Linux kernel has a security feature designed to block such attacks, `protected_symlinks`. On the rare systems with this purposefully disabled, it's then possible to trick Incus intro truncating and altering the mode and permissions of arbitrary files on the filesystem, leading to a potential denial of service or possible local privilege escalation. Version 6.23.0 fixes the issue.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Linuxcontainers | Incus | < 6.23.0 |
Related Weaknesses (CWE)
References
- https://github.com/lxc/incus/security/advisories/GHSA-q9vp-3wcg-8p4xExploitVendor Advisory
- https://github.com/lxc/incus/security/advisories/GHSA-q9vp-3wcg-8p4xExploitVendor Advisory
FAQ
What is CVE-2026-33711?
CVE-2026-33711 is a vulnerability with a CVSS score of 7.8 (HIGH). Incus is a system container and virtual machine manager. Incus provides an API to retrieve VM screenshots. That API relies on the use of a temporary file for QEMU to write the screenshot to which is t...
How severe is CVE-2026-33711?
CVE-2026-33711 has been rated HIGH with a CVSS base score of 7.8/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-33711?
Check the references section above for vendor advisories and patch information. Affected products include: Linuxcontainers Incus.