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.
CVE-2026-66897
“—” beside the score: it is equal to the CVSS score beside it.
This critical-severity CVE scores 9.9 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.7% (52nd percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.
- High severity, but no confirmed exploitation yet
Upgrade to LXD versions 4.0.13, 5.0.9, 5.21.7, 6.10 or later (from the CVE record's solution, Canonical Ltd.) — apply it.
- CVSS v3
- 9.9
- EG Score
- 9.9CRITICALmedium confidence
- EG Risk
- 45EG Risk 45/100
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 (value × EchelonGraph’s weight)Severity99% × 45%The EG Score, 9.9 of 10.Exploitation0.7% × 40%FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.Automatability0% × 15%CISA's SSVC Automatable value: no (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.Action: Upgrade to LXD versions 4.0.13, 5.0.9, 5.21.7, 6.10 or later (from the CVE record's solution, Canonical Ltd.). Apply it within your standard update timelines. - EPSS PROB
- 0.7%
- EPSS %ILE
- 52nd
- KEV
- Not listed
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).
Upgrade to LXD versions 4.0.13, 5.0.9, 5.21.7, 6.10 or later (from the CVE record's solution, Canonical Ltd.). Apply it within your standard update timelines.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it
Published
August 24, 2026
Last Modified
September 11, 2026
Advisory Details (1)
Auto-updated Oct 9, 2026Instance template path traversal allows arbitrary host file write as root · Advisory · canonical/lxd · GitHub
https://github.com/canonical/lxd/security/advisories/GHSA-q39m-8fx9-42fvAffected Packages
(2 across 2 ecosystems)
Debian:12(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| lxd | 5.0.2+git20231211.1364ae4-1 ... 5.0.2-6 (17 versions) |
| — |
Debian:13(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| lxd | 5.0.2+git20231211.1364ae4-9 ... 5.0.2+git20231211.1364ae4-9+deb13u7 (8 versions) |
| — |
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 15× in last 7d / 52× in last 30d)
Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.
- 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-10-12 15:46 UTCEG score recompute
- 2026-10-11 19:31 UTCEG score recompute
- 2026-10-11 16:46 UTCEG score recompute
- 2026-10-11 14:07 UTCEG score recompute
- 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-10-10 13:13 UTCEG score recompute
- 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-10-09 05:00 UTCEG score recompute
- 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-10-08 04:16 UTCEG score recompute
- 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-10-06 16:42 UTCEG score recompute
- 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-10-05 17:57 UTCEG score recompute
- 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-10-05 01:28 UTCEG score recompute
- 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-10-03 16:33 UTCEG score recompute
- 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-10-02 19:19 UTCEG score recompute
- 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-10-01 21:08 UTCEG score recompute
- 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
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- 2026-09-30 20:19 UTCEG score recompute
- 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-09-30 07:18 UTCEG score recompute
- 2026-09-28 21:33 UTCEG score recompute
- 2026-09-28 15:16 UTCEG score recompute
- 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-09-27 14:34 UTCEG score recompute
- 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-09-27 00:44 UTCEG score recompute
- 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-09-24 16:54 UTCEG score recompute
- 2026-09-23 20:19 UTCEG score recompute
- 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.7% · 50th percentile
- 2026-09-22 19:39 UTCEG score recompute
- 2026-09-21 22:32 UTCEG score recompute
- 2026-09-20 21:52 UTCEG score recompute
- 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.7% · 50th percentile
- 2026-09-19 18:29 UTCEG score recompute
- 2026-09-18 21:55 UTCEG score recompute
- 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.7% · 50th percentile
- 2026-09-17 21:13 UTCEG score recompute
- 2026-09-16 14:17 UTCEG score recompute
- 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.7% · 50th percentile
- 2026-09-16 09:28 UTCEG score recompute
- 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.7% · 50th percentile
- 2026-09-15 03:51 UTCEG score recompute
- 2026-09-13 16:52 UTCEG score recompute
- 2026-09-12 16:13 UTCEG score recompute
- 2026-09-11 15:33 UTCEG score recompute
- 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.6% · 47th percentile
- 2026-09-11 13:40 UTCEG score recompute
- 2026-09-11 09:37 UTCEPSS rescoreEPSS 0.6% · 47th percentile
- 2026-09-10 12:57 UTCEG score recompute
- 2026-09-09 01:34 UTCEG score recompute
- 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.6% · 47th percentile
- 2026-09-07 19:28 UTCEG score recompute
- 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.6% · 47th percentile
- 2026-09-06 16:54 UTCEG score recompute
- 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.6% · 47th percentile
- 2026-09-05 16:15 UTCEG score recompute
- 2026-09-05 15:31 UTCEPSS rescoreEPSS 0.6% · 47th percentile
- 2026-09-04 15:29 UTCEG score recompute
- 2026-09-04 07:10 UTCEG score recompute
- 2026-09-04 05:07 UTCEPSS rescoreEPSS 0.6% · 47th percentile
- 2026-09-02 17:08 UTCEG score recompute
- 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.6% · 47th percentile
- 2026-09-01 16:19 UTCEG score recompute
- 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.6% · 47th percentile
- 2026-09-01 07:23 UTCEG score recompute
- 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.6% · 47th percentile
- 2026-08-30 22:22 UTCEG score recompute
- 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.6% · 47th percentile
- 2026-08-30 01:49 UTCEG score recompute
- 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-08-29 00:28 UTCEG score recompute
- 2026-08-28 21:42 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-08-27 14:58 UTCEG score recompute
- 2026-08-26 17:49 UTCEG score recompute
- 2026-08-26 14:47 UTCEPSS rescoreEPSS 0.6% · 47th percentile
- 2026-08-25 16:57 UTCEG score recompute
- 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-08-25 04:23 UTCEG score recompute
- 2026-08-25 04:10 UTCEG score recompute
- 2026-08-24 14:24 UTCEG score recompute
- 2026-08-24 13:22 UTCEG score recompute
- 2026-08-24 10:24 UTCEG score recompute
- 2026-08-24 09:28 UTCEG score recomputeFirst assessed: 9.9 CRITICAL
- 2026-08-24 09:27 UTCMITRE cvelistV5first tracked
Related CVEs(same product + same CWE)
Same product
10 shownDebian:12:lxd
Frequently asked(5)
What is CVE-2026-66897?
When was the CVE record for CVE-2026-66897 published?
Is CVE-2026-66897 actively exploited?
What is the CVSS score of CVE-2026-66897?
How do I remediate CVE-2026-66897?
Dependency Blast Radius
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