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Vulnerabilities/CVE-2026-66897Public Intelligence Dossier
Source: canonical · Limited verification•Last verified: •Collection Degraded
CVE-2026-66897Unknown / EvaluatingCRITICAL (raw)CVSS 9.9CWE-22

A path traversal vulnerability in LXD's instance template processing allows an attacker with container edit permissions, or any user launching a crafted image, to overwrite arbitrary files on the host system as root

Published: 24 Aug 2026•Last updated: 24 Oct 2026, 09:40 PM IST•Source identifier: security@ubuntu.com
Dossier completeness: source-provided sections 2 / 3 · rule guidance available. Missing source facts count as incomplete.
Official source
CISA KEV catalog
Unknown
KEV status was not determined.
CVSS score
9.9CRITICAL (raw)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Metric sourcesecurity@ubuntu.com
EPSS probability
0.7%0.007
Percentile54th
Weakness type
CWE-22
CWE-23
Remediation
Patch status unknown
No fixed version or KB recorded

Why It Matters

Analysis dossier

Why It Matters

A path traversal vulnerability in LXD's instance template processing allows an attacker with container edit permissions, or any user launching a crafted image, to overwrite arbitrary files on the host system as root. When processing target template paths specified in metadata.yaml, LXD validates the path against a confined os.Root directory handle but subsequently opens and creates the file using os.Create with an unconfined string path. This discrepancy between path resolution checks and file creation allows an attacker to escape directory confinement, overwrite root-owned host files, and achieve host root code execution.

SOC priority

High Severity / Review

Actively exploited (source statement)

Unknown

Publicly disclosed

Unknown

Risk basis: SOC ecosystem technology relevance; CRITICAL severity; Critical source severity without confirmed exploitation

Affected Products & Remediation

1 source-backed product
Affected products and versions (source)
  • canonical lxd · < 4.0.13; >= 5.0.0 < 5.0.9; >= 5.1 < 5.21.7; >= 6.0 <= 6.9 · NVD CPE · Source
Recorded patch / KBNot provided by source

Vendor or catalog guidance (source)

Not provided by source

Known exploitation (source facts)

Only what a source states. Unknown means no source has said either way; it is not "not exploited".

CISA KEV
Unknown
Exploited (source statement)
Unknown
Publicly disclosed (source)
Unknown

Suggested hunting (rule-based inference)

SecOps Signal recommendation (rule-based inference). These steps are hunting hypotheses from the vulnerability class; they do not state or imply that exploitation occurred here or anywhere.

Matched path-traversal (CWE-22)

Exposure

  1. Locate affected deployments and the path-handling endpoint named by the advisory.Telemetry: Application access logs · The affected path must come from the source, not the CWE alone. · Rule path-traversal

Exploitation evidence

  1. Review requests to that endpoint for traversal encodings and unusual file responses.Telemetry: Application access logs · Such patterns are a hypothesis to validate against normal traffic. · Rule path-traversal

Response

  1. Verify the source-stated fix and retest the affected path.Telemetry: Application change records · The exact remediation depends on the source advisory. · Rule path-traversal

CISA KEV Record

CISA KEV status was not determined for this record.

Change History & Source Data

— No recorded material change

CNA / source
security@ubuntu.com
Record status · verification
UPDATED · NVD API
CPE
cpe:2.3:a:canonical:lxd:*:*:*:*:*:*:*:*

Evidence & Provenance

2 public sources
github.comSource recordnvd.nist.govSource record

Linked by the query's stored exact CVE association. Review required tables and validation status before use.

Detection Hunting Query
Target: DeviceTvmSoftwareVulnerabilities•Defender XDR
Detect endpoints exposed to CVE-2026-66897
Purpose: Exposure assessment (Category: Exposure Check)Why linked: Query metadata names CVE-2026-66897
DeviceTvmSoftwareVulnerabilities| where CveId == "CVE-2026-66897"| project DeviceId, DeviceName, OSPlatform, OSVersion, SoftwareVendor, SoftwareName, SoftwareVersion, CveId, VulnerabilitySeverityLevel, RecommendedSecurityUpdate, RecommendedSecurityUpdateId| sort by VulnerabilitySeverityLevel desc
Schema Checked · Not runtime validatedSource: SecOps Signal deterministic template · Limited verificationStatic screening: Passed structure and schema checks; tenant execution is not verified.
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Correlated briefings

SecOps Signal surfaces public advisory facts only. A missing value means the source has not published it, not that your environment is unaffected. No tenant inventory is connected.