A side‑channel vulnerability in the BIP‑39 mnemonic processing routine enables an attacker with physical access to the device during the very first use to extract the recovery phrase. The flaw originates from timing variations and branching paths in the word‑search algorithms defined by the BIP‑39 standard, allowing a single trace to be analyzed with deep‑learning techniques. Recovery of the mnemonic directly compromises the holder’s funds, as it provides full ownership of the wallet’s private keys.

The weakness affects Trezor One (firmware versions 1.13.0‑1.14.0), Trezor T (firmware 1.13.0‑1.14.0), and Trezor Safe (firmware 1.13.0‑1.14.0). The issue is limited to these firmware releases; newer revisions are not impacted.

Because the attack requires only a single side‑channel trace collected during the initial setup and relies on well‑known deep‑learning crypto‑analysis, the exploitation risk is high for users who deploy the device in insecure physical environments. No public exploit code is known at the moment, but the vulnerability is already listed in vendor advisories and has no EPSS score or KEV listing. Security teams should treat it as a high‑severity flaw due to the direct financial loss it can cause.