CVE-2026-53603: Forgekeep Nebula-Mesh

High severity, CVSS 7.1. EPSS: 0.4% chance of exploitation in the next 30 days.

nebula-mesh is a self-hosted control plane for Slack Nebula mesh VPN. Prior to version 0.3.8, Operator session tokens are stored in plaintext in the operator_sessions table (the token column is the PRIMARY KEY). The session token is a 32-byte random hex value sent directly in a cookie and valid for 24 hours. Anyone who can read the database (backup, snapshot, file copy, or SQL-level disclosure) obtains every active session token and can hijack operator sessions directly, with no further authentication. This issue has been patched in version 0.3.8.

Affected products

• Forgekeep Nebula-Mesh: before 0.3.8 (fixed in 0.3.8)

Published 2026-09-04. Last modified 2026-09-08.