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.

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History

Fri, 27 Mar 2026 04:00:00 +0000

Type Values Removed Values Added
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.
Title Incus vulnerable to local privilege escalation through VM screenshot path
Weaknesses CWE-61
References
Metrics cvssV4_0

{'score': 4.7, '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'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-03-26T22:37:29.746Z

Reserved: 2026-03-23T17:06:05.747Z

Link: CVE-2026-33711

cve-icon Vulnrichment

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cve-icon NVD

Status : Received

Published: 2026-03-26T23:16:20.423

Modified: 2026-03-26T23:16:20.423

Link: CVE-2026-33711

cve-icon Redhat

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cve-icon OpenCVE Enrichment

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Weaknesses