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IncusApplication · Linuxcontainers

CVE-2026-23954

HIGH · 8.7 CVSS v3.1 Published 2026-01-22
Fix available
A fix is available. Upgrade to 6.21.0 or later.
See remediation →
89/100
Remediation priority · High
Public exploit Zero-click Patch available

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
Incus is a system container and virtual machine manager. Versions 6.21.0 and below allow a user with the ability to launch a container with a custom image (e.g a member of the ‘incus’ group) to use directory traversal or symbolic links in the templating functionality to achieve host arbitrary file read, and host arbitrary file write. This ultimately results in arbitrary command execution on the host. When using an image with a metadata.yaml containing templates, both the source and target paths are not checked for symbolic links or directory traversal. This can also be exploited in IncusOS. A fix is planned for versions 6.0.6 and 6.21.0, but they have not been released at the time of publication.

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
How this class of weakness works · CWE-22

A file path is built from user input without being confined, so sequences like “../” let an attacker step outside the intended directory. That can expose configuration, credentials, or source code, and in the worst case lets an attacker write files where they shouldn't. A durable fix resolves and canonicalises the path, then rejects anything that escapes a known-safe base directory.

General guidance for the path traversal class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

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
IncusApplication
Affected:<= 6.0.5>= 6.1.0, < 6.21.0

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
Adjacent
Complexity
Low
Privileges
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
None

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

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 6.21.0 or later
Fixed in 6.21.0
Vendor patch github.com →
Recommended fix Moderate confidence

Incus >= 6.0.6 (for 6.0.x branch) or Incus >= 6.21.0 (for 6.1.x+ branch)

  1. 1. Check the current installed Incus version using: incus --version or incusd --version
  2. 2. If running version <= 6.0.5 or >= 6.1.0 and < 6.21.0, plan for upgrade to the fixed release
  3. 3. Review the Incus release notes or GitHub releases page for the availability of versions 6.0.6 and 6.21.0
  4. 4. Before upgrading, ensure backups of Incus storage pools and configurations are available
  5. 5. Upgrade Incus using the distribution's package manager or official Incus installation method
  6. 6. After upgrade, verify the version is >= 6.0.6 (for 6.0.x branch) or >= 6.21.0 (for 6.1.x+ branch)
  7. 7. If using custom images with metadata.yaml templates, ensure the patch has been applied to prevent exploitation
  8. 8. Restrict container image usage to trusted sources until upgrade is complete
Caveat Review Incus release notes for any breaking changes between current version and target fixed version; minor point releases typically have minimal breaking changes

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

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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-2026-23954 in production — separate from our analysis above.

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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
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