PeckShieldAlert has sounded the alarm after hackers attacked 402Bridge, stealing about $17,000 in USDC. The security firm found suspicious activity that affected more than 200 users. The breach happened just days after the project went live, and the x402 payment protocol gained traction among crypto users.
The incident quickly spread across the crypto community, with security firms urging users to revoke any active authorizations linked to the compromised address. “402bridge has been exploited. ~17K $USDC was stolen. Please revoke your allowance, if any, to 0xed..9FC5,” PeckShieldAlert said in an X post.
Private key exposure behind the exploit
The 402Bridge team explained that the attack stemmed from a critical design flaw in its backend process. “The x402 mechanism requires users to sign or approve transactions via the web interface, which are then sent to a backend server,” the protocol said on X. The server uses an admin private key to call contract methods, which, when connected to the internet, exposes administrative privileges.
Moreover, this setup may have allowed hackers to access the private key and redirect user funds. According to Slowmist Founder Cos, the hacker wallet address ‘0x2b8F’ took about $17,693 in USDC before converting it into 4.2 ETH. The hacker then moved the stolen ETH to Arbitrum through several transactions, making it nearly impossible to recover the funds.
Security warnings and industry reactions
After the hack, Web3 security company GoPlus Security warned users to cancel any active approvals linked to 402Bridge. The firm urged everyone to double-check that they’re using the project’s official contract addresses before allowing any transactions. Experts also advised users to only approve small amounts and to review their wallet permissions often to stay safe.
The x402 protocol made headlines this week for making instant payments possible through the HTTP 402 system. It handled over 932,000 transactions in the week ending October 20, 2025, showing strong momentum before the recent hack suddenly brought everything to a stop.
This attack shows how dangerous it can be when private keys aren’t well-protected. Developers must find safer ways to guard them, and users should stay alert by checking what they approve and keeping control of their own wallets.
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