Executive brief
nebula-mesh is a tool used to manage secure, private networks. A flaw in the software prevents the system from actually revoking access for blocked or compromised users. In practice, this means that even if an administrator 'blocks' a device, that device can continue to access the private network and its sensitive data for up to a year, creating a significant security gap.
Technical details
The vulnerability exists because the nebula-mesh agent decodes the 'blocklist' JSON field from the server's update response but subsequently discards it without updating the local configuration. Additionally, the configuration generator lacks the logic to emit the 'pki.blocklist' field into the agent's config.yml. This results in a failure to enforce certificate revocation at the peer level (CWE-299). An attacker with exfiltrated host credentials can maintain network access despite being revoked in the management UI. The issue is resolved in version 0.7.1 by ensuring the blocklist is correctly propagated and applied to the agent's configuration.
Affected products
- forgekeep nebula-mesh < 0.7.1
Timeline
- 2026-06-23: disclosed
- 2026-07-14: advisory
- 2026-07-14: patched: Fixed in version 0.7.1