WireGuard Easy versions up to 15.3.0 generate one‑time link tokens with a cryptographic weakness. The token is derived from a CRC32 checksum of a random number limited to 0–999, so at most 1000 possibilities exist for each client ID. An attacker exploiting this can brute‑force the token through the unauthenticated /cnf/:oneTimeLink endpoint, read the resulting JSON, and recover the associated WireGuard peer’s PrivateKey and PresharedKey. With those secrets the attacker can impersonate the peer and compromise VPN confidentiality and integrity.

The affected software is WireGuard Easy version 15.3.0 or earlier, released by the WireGuard Easy project under the wg-easy vendor name. The weaknesses are classified as CWE‑338 (Improper Encryption) and CWE‑613 (Information Exposure Through Broken Authentication).

The CVSS score of 9 indicates critical severity. EPSS score is below 1%, suggesting low current exploitation probability, yet the brute‑forceable keyspace and an unauthenticated, unrestricted endpoint allow attackers to scale this in the wild with simple HTTP requests to /cnf/:oneTimeLink. The vulnerability is not yet listed in the CISA KEV catalog, but it poses a serious risk to VPN operations if an attacker can discover and enumerate tokens.