CVE-2026-66897

CRITICALPre-NVD 9.99.9
EchelonGraph scoreMEDIUM confidence

“—” 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.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
9.9EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.7%CVSS: 9.9Exploit: None knownExposed services: Not assessed

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.

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
9.9CRITICALmedium confidence
EG Risk
45
EG 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, 2026
Fix named in the CVE record's solution (Canonical Ltd.). Sources: github.
GitHub advisoryMentions a patch (unverified)

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

Affected Packages

(2 across 2 ecosystems)
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
lxd5.0.2+git20231211.1364ae4-1 ... 5.0.2-6 (17 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
lxd5.0.2+git20231211.1364ae4-9 ... 5.0.2+git20231211.1364ae4-9+deb13u7 (8 versions)
  • every version on: no fix on record
—

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.

  1. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  2. 2026-10-12 15:46 UTCEG score recompute
  3. 2026-10-11 19:31 UTCEG score recompute
  4. 2026-10-11 16:46 UTCEG score recompute
  5. 2026-10-11 14:07 UTCEG score recompute
  6. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  7. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  8. 2026-10-10 13:13 UTCEG score recompute
  9. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  10. 2026-10-09 05:00 UTCEG score recompute
  11. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  12. 2026-10-08 04:16 UTCEG score recompute
  13. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  14. 2026-10-06 16:42 UTCEG score recompute
  15. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  16. 2026-10-05 17:57 UTCEG score recompute
  17. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  18. 2026-10-05 01:28 UTCEG score recompute
  19. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  20. 2026-10-03 16:33 UTCEG score recompute
  21. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  22. 2026-10-02 19:19 UTCEG score recompute
  23. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  24. 2026-10-01 21:08 UTCEG score recompute
  25. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
Show 68 more
  1. 2026-09-30 20:19 UTCEG score recompute
  2. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  3. 2026-09-30 07:18 UTCEG score recompute
  4. 2026-09-28 21:33 UTCEG score recompute
  5. 2026-09-28 15:16 UTCEG score recompute
  6. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  7. 2026-09-27 14:34 UTCEG score recompute
  8. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  9. 2026-09-27 00:44 UTCEG score recompute
  10. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  11. 2026-09-24 16:54 UTCEG score recompute
  12. 2026-09-23 20:19 UTCEG score recompute
  13. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  14. 2026-09-22 19:39 UTCEG score recompute
  15. 2026-09-21 22:32 UTCEG score recompute
  16. 2026-09-20 21:52 UTCEG score recompute
  17. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  18. 2026-09-19 18:29 UTCEG score recompute
  19. 2026-09-18 21:55 UTCEG score recompute
  20. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  21. 2026-09-17 21:13 UTCEG score recompute
  22. 2026-09-16 14:17 UTCEG score recompute
  23. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  24. 2026-09-16 09:28 UTCEG score recompute
  25. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  26. 2026-09-15 03:51 UTCEG score recompute
  27. 2026-09-13 16:52 UTCEG score recompute
  28. 2026-09-12 16:13 UTCEG score recompute
  29. 2026-09-11 15:33 UTCEG score recompute
  30. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  31. 2026-09-11 13:40 UTCEG score recompute
  32. 2026-09-11 09:37 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  33. 2026-09-10 12:57 UTCEG score recompute
  34. 2026-09-09 01:34 UTCEG score recompute
  35. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  36. 2026-09-07 19:28 UTCEG score recompute
  37. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  38. 2026-09-06 16:54 UTCEG score recompute
  39. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  40. 2026-09-05 16:15 UTCEG score recompute
  41. 2026-09-05 15:31 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  42. 2026-09-04 15:29 UTCEG score recompute
  43. 2026-09-04 07:10 UTCEG score recompute
  44. 2026-09-04 05:07 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  45. 2026-09-02 17:08 UTCEG score recompute
  46. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  47. 2026-09-01 16:19 UTCEG score recompute
  48. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  49. 2026-09-01 07:23 UTCEG score recompute
  50. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  51. 2026-08-30 22:22 UTCEG score recompute
  52. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  53. 2026-08-30 01:49 UTCEG score recompute
  54. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  55. 2026-08-29 00:28 UTCEG score recompute
  56. 2026-08-28 21:42 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  57. 2026-08-27 14:58 UTCEG score recompute
  58. 2026-08-26 17:49 UTCEG score recompute
  59. 2026-08-26 14:47 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  60. 2026-08-25 16:57 UTCEG score recompute
  61. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  62. 2026-08-25 04:23 UTCEG score recompute
  63. 2026-08-25 04:10 UTCEG score recompute
  64. 2026-08-24 14:24 UTCEG score recompute
  65. 2026-08-24 13:22 UTCEG score recompute
  66. 2026-08-24 10:24 UTCEG score recompute
  67. 2026-08-24 09:28 UTCEG score recomputeFirst assessed: 9.9 CRITICAL
  68. 2026-08-24 09:27 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-66897?
CVE-2026-66897 is a critical-severity vulnerability; its CVE record was 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 the CVE record for CVE-2026-66897 published?
The CVE record for CVE-2026-66897 was published on August 24, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 11, 2026; the record at its source may have been updated since.
Is CVE-2026-66897 actively exploited?
CVE-2026-66897 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.7% probability of exploitation in the next 30 days (52nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-66897?
CVE-2026-66897 has a CVSS base score of 9.9 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-66897?
The CVE record's solution for CVE-2026-66897, written by its CNA Canonical Ltd., names the fix: "Upgrade to LXD versions 4.0.13, 5.0.9, 5.21.7, 6.10 or later."

Dependency Blast Radius

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