CVE-2025-43866 Vantage6 Server JWT secret not cryptographically secure
The vantage6 server uses a predictable UUID1 for its JWT secret, allowing attackers to forge tokens and bypass authentication.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-43866?
CVE-2025-43866 is a low-severity vulnerability in vantage6, published on 12 Jun 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-330
Which versions are affected by CVE-2025-43866?
3 open source packages ship an affected version, including vantage6-server. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
vantage6-server PyPI | All versions | 4.11.0 |
vantage6-server PyPI | All versions | 4.11.0 |
vantage6-server PyPI | All versions | 4.11.0 |
Products include Vantage6 Vantage6.
How do I fix CVE-2025-43866?
Upgrade vantage6-server to 4.11.0 or later.
Is CVE-2025-43866 being exploited?
There is no known exploitation of CVE-2025-43866 in the wild and no public exploit code.
Other vulnerabilities in vantage6
- CVE-2024-21649 Remote code execution
- CVE-2023-23929 Refresh tokens do not expire in Vantage6
- CVE-2023-47631 vantage6 Node accepts non-whitelisted algorithms from malicious server
- CVE-2024-21653 vantage6 insecure SSH configuration for node and server containers
- CVE-2023-22738 Improper Preservation of Permissions in vantage6
Sources
Also known as GHSA-m3mq-f375-5vgh, PYSEC-2025-221.