lxc incus up to 6.22.x protected_symlinks

Summaryinfo

A vulnerability labeled as critical has been found in lxc incus up to 6.22.x. This affects the function protected_symlinks. The manipulation results in symlink. This vulnerability is known as CVE-2026-33711. Attacking locally is a requirement. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as critical has been found in lxc incus up to 6.22.x. Affected is the function protected_symlinks. The manipulation with an unknown input leads to a symlink vulnerability. CWE is classifying the issue as CWE-61. The 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. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is traded as CVE-2026-33711 since 03/23/2026. The exploitability is told to be easy. Local access is required to approach this attack. Technical details are known, but there is no available exploit.

Upgrading to version 6.23.0 eliminates this vulnerability.

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Productinfo

Vendor

• lxc

Name

• incus

Version

• 6.0
• 6.1
• 6.2
• 6.3
• 6.4
• 6.5
• 6.6
• 6.7
• 6.8
• 6.9
• 6.10
• 6.11
• 6.12
• 6.13
• 6.14
• 6.15
• 6.16
• 6.17
• 6.18
• 6.19
• 6.20
• 6.21
• 6.22

Website

• Product: https://github.com/lxc/incus/

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