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CVE-2026-63297· NVD / CVE Program· CNA canonical

Cross-project instance copy bypasses target project restrictions via TOCTOU in config merge

An authorization bypass vulnerability in LXD due to a timing flaw during configuration merging allows an authenticated attacker to bypass target project restrictions during cross-project instance copies. When copying an instance to a target project, LXD performs restriction checks before configuration merging is complete, creating a time-of-check to time-of-use (TOCTOU) condition. An attacker can exploit this flaw to copy instances with disallowed high-privilege configurations into restricted projects, bypassing security controls.

CriticalCVSS 9.9 · v3.1—No exploit Fix available
Published
Aug 12, 2026
Updated
Sep 11, 2026
EPSS
0.3% · 25th percentile
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Report tools

JSON

Action score

39

Monitor

Low priority for now.

CVSS
39 / 40 · 9.9 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
proof of concept
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · canonical
9.9
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.

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 lxd5.0.0 and later · before 5.0.8
  • canonical lxd5.1 and later · before 5.21.6
  • canonical lxd6.0 and later · before 6.9

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

    • 5.0.0 and later · before 5.0.8affected · semver
    • 5.21.0 and later · before 5.21.6affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12lxdall versions—
openSUSE:Leap 16.0lxdbefore 5.21.6-bp160.1.15.21.6-bp160.1.1

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 LXD5.0.8Vendor (CNA)
Canonical LXD5.21.6Vendor (CNA)
openSUSE:lxd5.21.6-bp160.1.1 · openSUSE:Leap 16.0Package registry (OSV)

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.

No nightly-computed relations.

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
high · data or configuration can be modified
Availability
high · the service can be disrupted

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
High
Availability impact
High

Weakness class (CWE)

CWE-367 · Time-of-check Time-of-use (TOCTOU) Race Condition

CVSS vector

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

nvd-secondary

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

—

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

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Change log

  1. Fix✗ → ✓

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