dbcve.org
Ubuntu LinuxOperating system · Canonical

CVE-2023-5536

MEDIUM · 6.4 CVSS v3.1 Published 2023-12-12
Fix available
A fix is available. Upgrade to 24.04 or later.
See remediation →
66/100
Remediation priority · Elevated
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A feature in LXD (LP#1829071), affects the default configuration of Ubuntu Server which allows privileged users in the lxd group to escalate their privilege to root without requiring a sudo password.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

This is a privilege escalation vulnerability in LXD where members of the lxd group can escalate to root privileges without requiring a sudo password, due to a default configuration issue in Ubuntu Server.

MitigationReview and harden the LXD group membership and default configurations to prevent unprivileged access to root. Consider removing unnecessary users from the lxd group or updating LXD to a patched version.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Ubuntu LinuxOperating system
Affected:< 24.04

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
High
Privileges
High
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify LXD is installed
    Check for the existence of LXD by running 'which lxd' or 'which lxc' to locate the LXD/LXC binaries, or check if the lxd service exists via 'systemctl list-unit-files | grep lxd'
    Affected if LXD binaries or service are found on the system
  2. Check for lxd group membership
    Run 'getent group lxd' to list all members of the lxd group, or use 'groups' command for the current user to see if they belong to the lxd group
    Affected if Any user account other than root is a member of the lxd group
  3. Verify LXD daemon is operational
    Attempt to run 'lxc list' or 'lxc info' to confirm the LXD daemon is running and accessible (may require sudo privileges depending on configuration)
    Affected if The LXD daemon responds to commands without requiring root or sudo password authentication
  4. Confirm Ubuntu version
    Run 'cat /etc/lsb-release' or 'lsb_release -a' to check the Ubuntu release version
    Affected if The system is running Canonical Ubuntu Linux with a version earlier than 24.04 and has LXD installed with lxd group users

A user is affected if they are running Ubuntu Linux versions prior to 24.04, have LXD installed, and have user accounts belonging to the lxd group that can access LXD without password authentication.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 24.04 or later
Fixed in 24.04
Interim mitigation

Review and harden the LXD group membership and default configurations to prevent unprivileged access to root. Consider removing unnecessary users from the lxd group or updating LXD to a patched version.

Recommended fix Moderate confidence

Ubuntu 24.04 (Noble Numbat)

  1. Ensure all critical data is backed up before upgrading
  2. Update current package lists: sudo apt update
  3. Install the update-manager-core package if not present: sudo apt install update-manager-core
  4. Edit /etc/update-manager/release-upgrades and set Prompt=normal
  5. Start the upgrade process: sudo do-release-upgrade
  6. Follow the on-screen prompts to complete the upgrade to Ubuntu 24.04
  7. Reboot the system when prompted
  8. After reboot, verify LXD group membership and test that the privilege escalation vulnerability is closed
Caveat Major Ubuntu upgrade may have breaking changes to existing packages, configurations, or require reinstallation of some applications; test in non-production environment first

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Ubuntu Linux Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,272.

Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-5536 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data