On September 7, 2026, the Ethereum Foundation announced that Ethereum L1 should become quantum-resistant by December 2029.
The attack in question is called Shor's algorithm: a quantum method that derives the matching private key from a known public key.
Why the public key on Ethereum is almost always exposed Here is the point at which most coverage passes your actual question by.
The quantum risk does not attach to the coin; it attaches to whether the public key of an address is known.
Checking Ethereum's quantum risk: what to take away Stay calm and sell nothing.