CVE-2026-31309 [CRITICAL] – Improper authorization in the /tequilapi/config/user endpoint of Mysterium Node from v1.21

Improper authorization in the /tequilapi/config/user endpoint of Mysterium Node from v1.21.1-rc0 before v1.36.0 allows an unauthenticated attacker to arbitrarily overwrite the node’s configuration and achieve a full node takeover via a crafted POST request.