UBUNTU-CVE-2026-33711

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Source
https://ubuntu.com/security/CVE-2026-33711
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33711.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-33711
Upstream
Published
2026-03-26T23:16:00Z
Modified
2026-05-20T16:25:30.192016464Z
Severity
  • 4.7 (Medium) CVSS_V4 - 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 CVSS Calculator
  • 7.8 (High) CVSS_V3 - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

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.

References

Affected packages

Ubuntu:Pro:24.04:LTS / incus

Package

Name
incus
Purl
pkg:deb/ubuntu/incus?arch=source&distro=esm-apps%2Fnoble

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

0.*
0.4-1ubuntu1
0.5.1-1
0.5.1-3
0.6-1
6.*
6.0.0-1
6.0.0-1ubuntu0.1
6.0.0-1ubuntu0.2
6.0.0-1ubuntu0.2+esm1
6.0.0-1ubuntu0.3
6.0.0-1ubuntu0.3+esm1
6.0.0-1ubuntu0.3+esm2
6.0.0-1ubuntu0.3+esm3

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "golang-github-lxc-incus-dev",
            "binary_version": "6.0.0-1ubuntu0.3+esm3"
        },
        {
            "binary_name": "incus",
            "binary_version": "6.0.0-1ubuntu0.3+esm3"
        },
        {
            "binary_name": "incus-agent",
            "binary_version": "6.0.0-1ubuntu0.3+esm3"
        },
        {
            "binary_name": "incus-client",
            "binary_version": "6.0.0-1ubuntu0.3+esm3"
        },
        {
            "binary_name": "incus-migrate",
            "binary_version": "6.0.0-1ubuntu0.3+esm3"
        },
        {
            "binary_name": "incus-tools",
            "binary_version": "6.0.0-1ubuntu0.3+esm3"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33711.json"

Ubuntu:25.10 / incus

Package

Name
incus
Purl
pkg:deb/ubuntu/incus?arch=source&distro=questing

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

6.*
6.0.3-4
6.0.4-2

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "golang-github-lxc-incus-dev",
            "binary_version": "6.0.4-2"
        },
        {
            "binary_name": "incus",
            "binary_version": "6.0.4-2"
        },
        {
            "binary_name": "incus-agent",
            "binary_version": "6.0.4-2"
        },
        {
            "binary_name": "incus-base",
            "binary_version": "6.0.4-2"
        },
        {
            "binary_name": "incus-client",
            "binary_version": "6.0.4-2"
        },
        {
            "binary_name": "incus-extra",
            "binary_version": "6.0.4-2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33711.json"

Ubuntu:26.04:LTS / incus

Package

Name
incus
Purl
pkg:deb/ubuntu/incus?arch=source&distro=resolute

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

6.*
6.0.4-2
6.0.5-8

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "golang-github-lxc-incus-dev",
            "binary_version": "6.0.5-8"
        },
        {
            "binary_name": "incus",
            "binary_version": "6.0.5-8"
        },
        {
            "binary_name": "incus-agent",
            "binary_version": "6.0.5-8"
        },
        {
            "binary_name": "incus-base",
            "binary_version": "6.0.5-8"
        },
        {
            "binary_name": "incus-client",
            "binary_version": "6.0.5-8"
        },
        {
            "binary_name": "incus-extra",
            "binary_version": "6.0.5-8"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33711.json"