Mobile phone chipmaker MediaTek patched a vulnerability affecting its chipsets in January that could have allowed an attacker to steal crypto seed phrases on affected devices using just a USB cable and the right software.
The flaw was discovered by Ledger’s white-hat security team, Donjon, who had shared the vulnerability with MediaTek before a patch was rolled out on Jan. 5, though users who have not installed the latest security patches are advised to do so, said Ledger.
Test device compromised in 45 seconds
According to Ledger, the flaw came from MediaTek’s secure boot chain, a security mechanism built into its chips that ensures a phone starts safely and only with authorized software during startup.
In a statement shared with Cointelegraph, Ledger explained that the flaw meant an attacker with access to an Android phone could connect it to a computer via USB and bypass security protections, potentially gaining access to sensitive data on the device, including crypto wallet seed phrases.
Around 25% of Android phones use the Trustonic Trusted Execution Environment (TEE) and MediaTek processors, which the security flaw exploits.
Donjon demonstrated the hack by connecting a Nothing CMF Phone 1 to a laptop and compromising the device’s security in approximately 45 seconds.
“Without ever even booting into Android, the exploit automatically recovered the phone’s PIN, decrypted its storage, and extracted the seed phrases from the most popular software wallets: Trust Wallet, Base, Kraken Wallet, Rabby, Tangem’s Mobile Wallet and Phantom,” Ledger said.
While Ledger urged users to update their devices, a Ledger spokesperson told Cointelegraph they “don’t anticipate this to be an ongoing issue.”
Mobile phones are never safe, Ledger says
With almost 36 million people managing digital assets on their phones as of early 2025, even a single vulnerability could put a significant number of wallets at risk.
In December 2025, Ledger revealed that it tested an attack on the MediaTek Dimensity 7300 (MT6878), and bypassed its security measures to gain “full and absolute control over the smartphone, with no security barrier left standing.”
Ledger chief technology officer Charles Guillemet told Cointelegraph in June 2020 that mobile phones, whether Android or iPhone, are “very difficult to have secure applications.”
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He reinforced a similar view on Wednesday, posting on X: “Smartphones aren’t built for security. Even when powered off, user data – including pins & seeds – can be extracted in under a minute.”
“This research highlights a fundamental architectural difference: General-purpose chips are built for convenience. Secure Elements are built for key protection. A dedicated Secure Element isolates secrets from the rest of the system, protecting them even under physical attack,” he said.
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