High
incus — security advisory
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.
- Products
- incus
- Affected versions
- 0.4-1ubuntu1, 0.5.1-1, 0.5.1-3, 0.6-1, 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, 6.0.3-4, 6.0.4-2, 6.0.5-8, 6.0.5-8ubuntu0.26.04.1~esm1, 7.0.1-5
- Fixed versions
- Not specified
- CVEs
- CVE-2026-33711
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 02:08 UTC · Revision 1
Source evidence
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.
osv:UBUNTU-CVE-2026-33711
incus
Fixed versions: Not specified
incus
Fixed versions: Not specified
incus
Fixed versions: Not specified
incus
Fixed versions: Not specified
Complete source record
{
"id": "23b4dbb34627accea7d6125de5450e768f64d0db9d646ff0108b8005ec29bb8d",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-33711",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-33711",
"summary": "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.",
"evidence": "osv:UBUNTU-CVE-2026-33711",
"products": [
{
"name": {
"value": "incus",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "0.4-1ubuntu1",
"evidence": "/affected/0/versions"
},
{
"value": "0.5.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "0.5.1-3",
"evidence": "/affected/0/versions"
},
{
"value": "0.6-1",
"evidence": "/affected/0/versions"
},
{
"value": "6.0.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "6.0.0-1ubuntu0.1",
"evidence": "/affected/0/versions"
},
{
"value": "6.0.0-1ubuntu0.2",
"evidence": "/affected/0/versions"
},
{
"value": "6.0.0-1ubuntu0.2+esm1",
"evidence": "/affected/0/versions"
},
{
"value": "6.0.0-1ubuntu0.3",
"evidence": "/affected/0/versions"
},
{
"value": "6.0.0-1ubuntu0.3+esm1",
"evidence": "/affected/0/versions"
},
{
"value": "6.0.0-1ubuntu0.3+esm2",
"evidence": "/affected/0/versions"
},
{
"value": "6.0.0-1ubuntu0.3+esm3",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "incus",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "6.0.3-4",
"evidence": "/affected/1/versions"
},
{
"value": "6.0.4-2",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "incus",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "6.0.5-8",
"evidence": "/affected/2/versions"
},
{
"value": "7.0.1-5",
"evidence": "/affected/2/versions"
}
]
},
{
"name": {
"value": "incus",
"evidence": "/affected/3/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "6.0.4-2",
"evidence": "/affected/3/versions"
},
{
"value": "6.0.5-8",
"evidence": "/affected/3/versions"
},
{
"value": "6.0.5-8ubuntu0.26.04.1~esm1",
"evidence": "/affected/3/versions"
}
]
}
],
"severity": "high",
"structured": {
"id": "UBUNTU-CVE-2026-33711",
"aliases": [
"UBUNTU-CVE-2026-33711"
],
"metrics": [
{
"type": "CVSS_V4",
"score": "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"
},
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
},
{
"type": "Ubuntu",
"score": "medium"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "incus",
"purl": "pkg:deb/ubuntu/incus?arch=source&distro=esm-apps%2Fnoble",
"ecosystem": "Ubuntu:Pro:24.04:LTS"
},
"versions": [
"0.4-1ubuntu1",
"0.5.1-1",
"0.5.1-3",
"0.6-1",
"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"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33711.json"
},
"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"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "incus",
"purl": "pkg:deb/ubuntu/incus?arch=source&distro=questing",
"ecosystem": "Ubuntu:25.10"
},
"versions": [
"6.0.3-4",
"6.0.4-2"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33711.json"
},
"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"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "incus",
"purl": "pkg:deb/ubuntu/incus?arch=source&distro=stonking",
"ecosystem": "Ubuntu:26.10"
},
"versions": [
"6.0.5-8",
"7.0.1-5"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33711.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "golang-github-lxc-incus-dev",
"binary_version": "7.0.1-5"
},
{
"binary_name": "incus",
"binary_version": "7.0.1-5"
},
{
"binary_name": "incus-agent",
"binary_version": "7.0.1-5"
},
{
"binary_name": "incus-base",
"binary_version": "7.0.1-5"
},
{
"binary_name": "incus-client",
"binary_version": "7.0.1-5"
},
{
"binary_name": "incus-extra",
"binary_version": "7.0.1-5"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "incus",
"purl": "pkg:deb/ubuntu/incus?arch=source&distro=esm-apps%2Fresolute",
"ecosystem": "Ubuntu:Pro:26.04:LTS"
},
"versions": [
"6.0.4-2",
"6.0.5-8",
"6.0.5-8ubuntu0.26.04.1~esm1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33711.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "golang-github-lxc-incus-dev",
"binary_version": "6.0.5-8ubuntu0.26.04.1~esm1"
},
{
"binary_name": "incus",
"binary_version": "6.0.5-8ubuntu0.26.04.1~esm1"
},
{
"binary_name": "incus-agent",
"binary_version": "6.0.5-8ubuntu0.26.04.1~esm1"
},
{
"binary_name": "incus-base",
"binary_version": "6.0.5-8ubuntu0.26.04.1~esm1"
},
{
"binary_name": "incus-client",
"binary_version": "6.0.5-8ubuntu0.26.04.1~esm1"
},
{
"binary_name": "incus-extra",
"binary_version": "6.0.5-8ubuntu0.26.04.1~esm1"
}
]
}
}
],
"modified": "2026-10-17T12:58:11.191489851Z",
"provider": "osv",
"upstream": [
"CVE-2026-33711"
],
"references": [
"https://ubuntu.com/security/CVE-2026-33711",
"https://www.cve.org/CVERecord?id=CVE-2026-33711",
"https://github.com/lxc/incus/pull/3092",
"https://github.com/lxc/incus/security/advisories/GHSA-q9vp-3wcg-8p4x"
]
},
"related_cves": [
{
"value": "CVE-2026-33711",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/1/score"
},
"source_id": "core-osv",
"document_id": 358304,
"published_at": "2026-03-26T23:16:00+00:00"
}