CVE-2026-66897

CRITICALPre-NVD 9.99.9—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.9 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.6%, top 53% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — 3 sources updated this week
9.9EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.9Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
9.9
EG Score
9.9(medium)
EG Risk
45(Track)
EG Risk 45/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity99% × 45%
Exploitation1% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
47%
KEV
Not listed

Published

August 24, 2026

Last Modified

August 25, 2026

Advisory Details (1)

Auto-updated Aug 25, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

Instance template path traversal allows arbitrary host file write as root · Advisory · canonical/lxd · GitHub

https://github.com/canonical/lxd/security/advisories/GHSA-q39m-8fx9-42fv

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 12× in last 7d / 12× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-27 14:58 UTCEG score recompute
  2. 2026-08-26 17:49 UTCEG score recompute
  3. 2026-08-26 14:47 UTCEPSS rescore
  4. 2026-08-25 16:57 UTCEG score recompute
  5. 2026-08-25 13:49 UTCEPSS rescore
  6. 2026-08-25 04:23 UTCEG score recompute
  7. 2026-08-25 04:10 UTCEG score recompute
  8. 2026-08-24 14:24 UTCEG score recompute
  9. 2026-08-24 13:22 UTCEG score recompute
  10. 2026-08-24 10:24 UTCEG score recompute
  11. 2026-08-24 09:28 UTCEG score recompute
  12. 2026-08-24 09:27 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-66897?
CVE-2026-66897 is a critical vulnerability published on August 24, 2026. 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…
When was CVE-2026-66897 disclosed?
CVE-2026-66897 was first published in the National Vulnerability Database on August 24, 2026, with the most recent update on August 25, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-66897 actively exploited?
CVE-2026-66897 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 52.9% of all scored CVEs.
What is the CVSS score of CVE-2026-66897?
CVE-2026-66897 has a CVSS v3 base score of 9.9 (NVD).
How do I remediate CVE-2026-66897?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-66897, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-66897

Explore →

Is Your Infrastructure Affected by CVE-2026-66897?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs