CVE-2026-33711: linuxcontainers incus UNIX Symbolic Link (Symlink) Following

Vulnerability summary

CVE-2026-33711 is a high (CVSS 7.8) UNIX Symbolic Link (Symlink) Following vulnerability in linuxcontainers incus. EPSS estimates a 0.18% chance of exploitation in the next 30 days, higher than 7.4% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 26-03-2026
   PublishedVulnerability first disclosed.
2. 27-03-2026
   Last modifiedVulnerability information updated.

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.

• CWE-61UNIX Symbolic Link (Symlink) FollowingThe product, when opening a file or directory, does not sufficiently account for when the file is a symbolic link that resolves to a target outside of the intended control sphere. This could allow an attacker to cause the product to operate on unauthorized files.