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CVE-2026-16033· NVD / CVE Program· CNA canonical

Arbitrary file read+write on host via templates/ symlink in malicious image

A path traversal vulnerability in LXD allows an attacker to achieve arbitrary host file read or unconstrained file creation. When processing image metadata templates, LXD fails to properly sanitize or restrict template file paths from escaping the instance templates directory (specifically affecting virtual machine / QEMU driver execution paths). An attacker can exploit this flaw by providing a crafted image archive with malicious template directives containing path traversal sequences, causing LXD to access or write files outside the intended template directory on the host system.

HighCVSS 8.5 · v3.1—No exploit Fix available
Published
Aug 12, 2026
Updated
Sep 11, 2026
EPSS
0.4% · 26th percentile
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Report tools

JSON

Action score

34

Monitor

Low priority for now.

CVSS
34 / 40 · 8.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

CISA SSVC decision

Exploitation
proof of concept
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · canonical
8.5
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

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Affected systems

VendorProduct
canonicallxd

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • canonical lxd4.0.0 and later · before 4.0.12
  • canonical lxd5.0.0 and later · before 5.0.7

Versions reported by the vendor

Affected version ranges reported by the assigning authority (canonical). Independent of NVD's CPE analysis and usually ahead of it.

  • Canonical LXD

    • 4.0.0 and later · before 4.0.12affected · semver
    • 5.0.0 and later · before 5.0.8affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12lxdall versions—

Same product

canonical: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-87799Arbitrary file write on LXD host via symlink in migration stream
    39Monitor
  • CVE-2026-85526Path traversal via Btrfs optimized-backup subvolumes[].path enables root file/dir manipulation in LXD
    39Monitor
  • CVE-2026-66897Instance template path traversal allows arbitrary host file write as root
    39Monitor
  • CVE-2026-66898Path traversal via unvalidated instance name in backup tarball restore enables root file write / RCE
    39Monitor
  • CVE-2026-63300Cross-project instance move bypasses all project restrictions allowing host command execution
    39Monitor
  • CVE-2026-63299Storage volume cross-project move and snapshot restore bypass project disk limits
    39Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Canonical LXD4.0.12Vendor (CNA)
Canonical LXD5.0.8Vendor (CNA)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-668980 days apartPath traversal via unvalidated instance name in backup tarball restore enables root file write / RCE
    39Monitor
  • CVE-2026-6689712 days apartInstance template path traversal allows arbitrary host file write as root
    39Monitor
  • CVE-2026-8552647 days apartPath traversal via Btrfs optimized-backup subvolumes[].path enables root file/dir manipulation in LXD
    39Monitor
  • CVE-2026-8518547 days apartPath traversal in LXD btrfs storage driver allows arbitrary file deletion and write on host as root
    38Monitor
  • CVE-2025-54293314 days apartPath Traversal in LXD Instance Log File Retrieval
    28Monitor
  • CVE-2025-54292314 days apartClient-Side Path Traversal in LXD-UI
    19Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
low · data or configuration can be modified
Availability
none

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Changed
Confidentiality impact
High
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-22 · Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

CVSS vector

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

nvd-secondary

Root cause

A user-supplied file name is joined with the allowed directory, but the result is never checked to confirm it is still inside that directory.

The bug in code

The whole CWE-22 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
const file = path.join(ROOT, req.query.name);res.sendFile(file);

Fixed

ts
const file = path.resolve(ROOT, req.query.name);if (!file.startsWith(ROOT + path.sep)) {  return res.sendStatus(400);}res.sendFile(file);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

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All records