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: 0.2% (13th percentile of EPSS-scored CVEs). 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: 0.2%CVSS: 8.4Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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
8.4HIGHmedium confidence
EG Risk
38
EG Risk 38/100CISA SSVC

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%
CISA SSVC: Track at low or medium mission impact; Track* at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.2%
EPSS %ILE
13th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 3, 2026

Last Modified

September 10, 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
githubMentions a patch (unverified)

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 rangeFix by version rangeDependents
ouroboros-ai0.1.0 ... 0.9.0 (537 versions)
  • every version up to 0.42.1: fixed in 0.42.1
—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 11× in last 7d / 43× 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.

Showing the most recent 100 of 113 total refreshes for this CVE.

  1. 2026-10-09 20:07 UTCEPSS rescore
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  1. 2026-09-22 03:53 UTCEG score recompute
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  75. 2026-08-08 16:37 UTCEPSS rescore

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PyPI:ouroboros-ai

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 on August 3, 2026, with the most recent update on September 10, 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 0.2% probability of exploitation in the next 30 days (13th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-66065?
CVE-2026-66065 has a CVSS base score of 8.4 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-66065?
A fix for CVE-2026-66065 is available: update to the fixed version the vendor names in its advisory.

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