CVE-2026-33711

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 v3 7.8 HIGH

7.8^/10

CVSS v3 : HIGH

Vector :

Exploitability : 1.8 / Impact : 5.9

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/lxc/incus/security/advisories/GHSA-q9vp-3wcg-8p4x	Exploit Vendor Advisory
https://github.com/lxc/incus/security/advisories/GHSA-q9vp-3wcg-8p4x	Exploit Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:linuxcontainers:incus:*:*:*:*:*:*:*:*

History

30 Mar 2026, 18:51

Type	Values Removed	Values Added
References	~~() https://github.com/lxc/incus/security/advisories/GHSA-q9vp-3wcg-8p4x -~~	() https://github.com/lxc/incus/security/advisories/GHSA-q9vp-3wcg-8p4x - Exploit, Vendor Advisory
CPE		cpe:2.3:a:linuxcontainers:incus::::::::
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 7.8
First Time		Linuxcontainers Linuxcontainers incus

Information

Published : 2026-03-26 23:16

Updated : 2026-03-30 18:51

NVD link : CVE-2026-33711

Mitre link : CVE-2026-33711

CVE.ORG link : CVE-2026-33711

JSON object : View

Products Affected

linuxcontainers

incus

CWE

CWE-61

UNIX Symbolic Link (Symlink) Following

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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. 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