EUVD-2025-209448
GHSA-fxwp-fxmc-jh57
Severity by source
AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Physical access required (AV:P); AC:H reflects need for specialized side-channel hardware and pre-trained DL-SCA model; C:H for full mnemonic recovery; no integrity or availability impact.
Primary rating from Vendor (mitre).
CVSS VectorVendor: mitre
Lifecycle Timeline
4DescriptionCVE.org
A side-channel vulnerability exists in the implementation of BIP-39 mnemonic processing, as observed in Trezor One v1.13.0 to v1.14.0, Trezor T v1.13.0 to v1.14.0, and Trezor Safe v1.13.0 to v1.14.0 hardware wallets. This originates from the BIP-39 standard guidelines, which induce non-constant time execution and specific branch patterns for word searching. An attacker with physical access during the initial setup phase can collect a single side-channel trace. By utilizing profiling-based Deep Learning Side-Channel Analysis (DL-SCA), the attacker can recover the mnemonic code and subsequently steal the assets. The issue was patched.
AnalysisAI
BIP-39 mnemonic processing in Trezor One, Trezor T, and Trezor Safe firmware v1.13.0-v1.14.0 leaks seed phrase data via non-constant-time execution, enabling full mnemonic recovery by a physically present attacker during initial device setup. An adversary who can capture a single power or electromagnetic side-channel trace and apply a pre-trained Deep Learning Side-Channel Analysis (DL-SCA) model can reconstruct the BIP-39 mnemonic and subsequently derive all private keys, resulting in total loss of cryptocurrency assets. No public exploit code has been identified and no active exploitation is confirmed; Trezor has issued a patch per their published vulnerability advisory.
Technical ContextAI
BIP-39 defines the standard for deriving human-readable mnemonic phrases (12-24 words) from entropy, which serve as the root secret for hierarchical-deterministic cryptocurrency wallets. The flaw, classified under CWE-385 (Covert Timing Channel), arises because the Trezor firmware's word-search routine during BIP-39 mnemonic processing does not execute in constant time - execution duration and branch paths vary depending on the mnemonic word values being processed. This violates the constant-time programming invariant essential for cryptographic implementations. An observer monitoring power draw or electromagnetic emissions can detect micro-variations correlated to specific word selections. Profiling-based DL-SCA exploits these statistical correlations by training a neural network on a reference device of the same model, then applying it to infer the word sequence from a captured trace. All three affected product lines (Trezor One, Trezor T, Trezor Safe) running firmware v1.13.0 through v1.14.0 share this implementation and are equally affected. CPE data provided by EUVD lists 'n/a,' so version boundaries are drawn from the CVE description directly.
RemediationAI
Update all affected Trezor devices (One, T, and Safe) to firmware versions released after v1.14.0, which Trezor confirms addresses the non-constant-time BIP-39 implementation per their advisory at https://trezor.io/vulnerability/fix-side-channel-in-bip-39-mnemonic-processing-when-unlocked. The exact patched firmware version number was not specified in the available references and should be confirmed directly with Trezor's release notes before upgrading. As a compensating control before patching, perform device initialization exclusively in physically secure, controlled environments free of unauthorized observers or covert measurement equipment, since the attack window is limited to the initial setup phase. If a device running vulnerable firmware was initialized in an environment that may have been compromised (e.g., received via untrusted supply chain, set up in a public or surveilled space), treat the mnemonic as potentially exposed and migrate all cryptocurrency assets to a freshly initialized wallet on patched firmware. There are no software-only workarounds for this hardware-level side-channel; physical security controls during setup are the only pre-patch mitigation.
Same weakness CWE-385 – Covert Timing Channel
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External POC / Exploit Code
Leaving vuln.today