Vulnerability · Published Mar 26, 2026 · Assigned by GitHub_M
CVE-2026-33711Incus vulnerable to local privilege escalation through VM screenshot path
Medium 4.7
In plain English
A medium-severity security flaw in incus from lxc. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 30% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:13 | incus | no fix listed | DEBIAN-CVE-2026-33711 |
| Debian:14 | incus | 6.0.6-2 | DEBIAN-CVE-2026-33711 |
| Go | github.com/lxc/incus | no fix listed | GO-2026-4885 |
| Go | github.com/lxc/incus/v6 | 6.23.0 | GO-2026-4885 |
| Go | github.com/lxc/incus/v6 | 6.23.0 | GHSA-q9vp-3wcg-8p4x |
| Ubuntu:25.10 | incus | no fix listed | UBUNTU-CVE-2026-33711 |
| Ubuntu:26.10 | incus | no fix listed | UBUNTU-CVE-2026-33711 |
Affected products (as reported)
Weakness: CWE-61 · Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P
References
- https://github.com/lxc/incus/security/advisories/GHSA-q9vp-3wcg-8p4x x_refsource_CONFIRM