CVE-2026-66065

HIGHPre-NVD 8.48.4—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.4 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 78% 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
8.4EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.4Exploit: None knownExposed: 0

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

Ouroboros is a local-first runtime for AI coding agents that records their actions and applies user-defined policies to constrain behavior. Versions prior to 0.42.1 have an incomplete denylist. Several execution-routing keys of the same RCE class were omitted, so a malicious cloned repo can still reach arbitrary command execution by shipping a .env (auto-loaded at import, with no review step). The CVE-2026-47211 fix added _UNTRUSTED_ENV_DENYLIST to stop an untrusted project-directory .env from redirecting execution, but it did not account for all keys. The backend config-home and MCP/plugin roots bypass the approval gate by pointing the nested agent, MCP servers, and plugin roster at attacker config. Other variables re-enable blocked local transports, replace sub-agent prompts, switch backends, and lower tool approval classes, further weakening the approval gate. This issue has been fixed in version 0.42.1.

CVSS v3
8.4
EG Score
8.4(medium)
EG Risk
38(Track)
EG Risk 38/100SSVC: 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
Severity84% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
22%
KEV
Not listed

Published

August 3, 2026

Last Modified

August 5, 2026

Advisory Details (2)

Auto-updated Aug 3, 2026
Patch available. Sources: github, github_release.
github_release Patch Available

v0.42.1

Patch available: Q00/ouroboros v0.42.1

https://github.com/Q00/ouroboros/releases/tag/v0.42.1
github Patch Available

Incomplete fix of CVE-2026-47211: untrusted project .env can still reach RCE via omitted execution-routing keys · Advisory · Q00/ouroboros · GitHub

Affected: 0.42.1. All listed keys were added to

https://github.com/Q00/ouroboros/security/advisories/GHSA-jv2h-4p9v-wf5w

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFixed inDependents
ouroboros-ai0.1.0 ... 0.9.0 (853 versions)0.42.1—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 12× in last 7d / 45× 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. 2026-08-25 18:32 UTCEG score recompute
  2. 2026-08-25 13:49 UTCEPSS rescore
  3. 2026-08-24 20:30 UTCEG score recompute
  4. 2026-08-24 09:28 UTCEG score recompute
  5. 2026-08-23 00:33 UTCEG score recompute
  6. 2026-08-23 00:19 UTCEPSS rescore
  7. 2026-08-22 02:37 UTCEG score recompute
  8. 2026-08-21 23:49 UTCEPSS rescore
  9. 2026-08-21 04:39 UTCEG score recompute
  10. 2026-08-20 22:56 UTCEPSS rescore
  11. 2026-08-19 19:41 UTCEG score recompute
  12. 2026-08-19 17:04 UTCEPSS rescore
  13. 2026-08-18 21:44 UTCEG score recompute
  14. 2026-08-18 13:48 UTCEPSS rescore
  15. 2026-08-17 23:48 UTCEG score recompute
  16. 2026-08-17 13:47 UTCEPSS rescore
  17. 2026-08-17 01:52 UTCEG score recompute
  18. 2026-08-16 14:56 UTCEPSS rescore
  19. 2026-08-16 03:56 UTCEG score recompute
  20. 2026-08-15 06:00 UTCEG score recompute
  21. 2026-08-15 01:30 UTCEPSS rescore
  22. 2026-08-14 08:03 UTCEG score recompute
  23. 2026-08-13 22:00 UTCEPSS rescore
  24. 2026-08-12 23:01 UTCEG score recompute
  25. 2026-08-12 13:51 UTCEPSS rescore
Show 20 more
  1. 2026-08-11 14:07 UTCEG score recompute
  2. 2026-08-11 03:07 UTCEG score recompute
  3. 2026-08-11 00:00 UTCEPSS rescore
  4. 2026-08-09 18:13 UTCEG score recompute
  5. 2026-08-09 13:47 UTCEPSS rescore
  6. 2026-08-08 20:17 UTCEG score recompute
  7. 2026-08-08 16:37 UTCEPSS rescore
  8. 2026-08-07 22:21 UTCEG score recompute
  9. 2026-08-07 00:25 UTCEG score recompute
  10. 2026-08-06 13:47 UTCEPSS rescore
  11. 2026-08-06 02:28 UTCEG score recompute
  12. 2026-08-05 19:17 UTCEPSS rescore
  13. 2026-08-05 19:17 UTCEPSS rescore
  14. 2026-08-05 15:31 UTCEG score recompute
  15. 2026-08-05 14:38 UTCEG score recompute
  16. 2026-08-04 19:18 UTCEG score recompute
  17. 2026-08-04 15:10 UTCEPSS rescore
  18. 2026-08-03 21:20 UTCEG score recompute
  19. 2026-08-03 20:43 UTCEG score recompute
  20. 2026-08-03 20:43 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-66065?
CVE-2026-66065 is a high vulnerability published on August 3, 2026. Ouroboros is a local-first runtime for AI coding agents that records their actions and applies user-defined policies to constrain behavior. Versions prior to 0.42.1 have an incomplete denylist. Several execution-routing keys of the same RCE class were omitted, so a malicious cloned repo can still…
When was CVE-2026-66065 disclosed?
CVE-2026-66065 was first published in the National Vulnerability Database on August 3, 2026, with the most recent update on August 5, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-66065 actively exploited?
CVE-2026-66065 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 78.3% of all scored CVEs.
What is the CVSS score of CVE-2026-66065?
CVE-2026-66065 has a CVSS v3 base score of 8.4 (NVD).
How do I remediate CVE-2026-66065?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-66065, 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

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