How severe is CVE-2026-47211?

No CVSS score has been assigned to CVE-2026-47211 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-47211?

CVE-2026-47211 affects the following packages: ouroboros-ai (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2026-47211?

Update ouroboros-ai to 0.39.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-47211 is resolved across your whole dependency graph.

How do I detect CVE-2026-47211 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ouroboros-ai, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-47211 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2026-47211 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-47211 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-47211?

CVE-2026-47211 has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 8th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-47211?

CVE-2026-47211 is classified as CWE-426 (CWE-426). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-47211 published, and has it been updated?

CVE-2026-47211 was published on August 3, 2026 and was last updated on September 12, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

Not in CISA KEV

CVE-2026-47211 — ouroboros-ai

Fix: Q00/ouroboros@4e70b76

CVE-2026-47211 is a CWE-426 vulnerability in ouroboros-ai. A fix is available for ouroboros-ai — see the affected versions and patch details below.

Ouroboros: Remote Code Execution via Untrusted Project-Directory .env

Also known asGHSA-c4m7-2gwp-vw76PYSEC-2026-2857

Published

Aug 3, 2026

Updated

Sep 12, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

A successful exploit gives an attacker total control of the affected component, not partial access.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-47211.

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs8th percentile — riskier than 8% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐍ouroboros-ai

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Impact

A Remote Code Execution (RCE) vulnerability was discovered in Ouroboros. If a user clones a malicious repository and runs Ouroboros commands within that directory, it can lead to arbitrary code execution and potential system takeover.

The vulnerability (CWE-426: Untrusted Search Path & CWE-15: External Control of System Setting) stems from Ouroboros loading the .env file from the current working directory. Prior to the patch, execution-affecting environment variables such as OUROBOROS_CLI_PATH, OPENCODE_CLI_PATH, and other backend selectors were accepted directly from this local .env. An attacker could include a malicious script in the repository and point the CLI path variable to it (e.g., OUROBOROS_CLI_PATH=./malicious_script.sh). When the user executes a command like ouroboros init or any command that instantiates the adapter, the malicious script is executed instead of the intended CLI.

Patches

The vulnerability has been patched in version 0.39.0 via PR #1078. The fix establishes a strict trust boundary by applying a denylist to project-local .env loading. It blocks execution-affecting environment variables (such as runtime selectors and CLI path overrides) from being loaded from the project directory. Explicit constructor overrides and trusted user-owned home configurations (~/.ouroboros/.env) remain fully functional.

Users are strongly advised to upgrade to version 0.39.0 or later.

Workarounds

If upgrading is not immediately possible, users must carefully inspect any .env file inside cloned repositories before running Ouroboros commands to ensure it does not contain unexpected OUROBOROS_*_CLI_PATH or OPENCODE_CLI_PATH overrides.

References

GitHub PR: https://github.com/Q00/ouroboros/pull/1078

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`ouroboros-ai`	all versions	0.39.0`pip install --upgrade 'ouroboros-ai==0.39.0'`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ouroboros-ai, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update ouroboros-ai to 0.39.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-47211 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

### Impact A Remote Code Execution (RCE) vulnerability was discovered in Ouroboros. If a user clones a malicious repository and runs Ouroboros commands within that directory, it can lead to arbitrary code execution and potential system takeover. The vulnerability (CWE-426: Untrusted Search Path & CWE-15: External Control of System Setting) stems from Ouroboros loading the `.env` file from the current working directory. Prior to the patch, execution-affecting environment variables such as `OUROBOROS_CLI_PATH`, `OPENCODE_CLI_PATH`, and other backend selectors were accepted directly from this lo

O3 Security · Impact-Aware SCA

Is CVE-2026-47211 in your dependencies?

Find it across PyPI, including transitive dependencies.

Scan my dependencies How O3 SCA works