Threats affecting pkg:pypi/web3-py

Web3.py 7.15.0 through 7.16.0 and 8.0.0b2 through 8.0.0 contains a server-side request forgery vulnerability because _check_ip_blocked() does not unwrap IPv4-mapped IPv6 addresses in CCIP Read URL validation. Malicious contracts can return OffchainLookup URLs with IPv4-mapped IPv6 hosts or AAAA records, making clients with CCIP Read enabled send requests to loopback, private, or link-local services.

web3.py allows you to interact with the Ethereum blockchain using Python. From 6.0.0b3 to before 7.15.0 and 8.0.0b2, web3.py implements CCIP Read / OffchainLookup (EIP-3668) by performing HTTP requests to URLs supplied by smart contracts in offchain_lookup_payload["urls"]. The implementation uses these contract-supplied URLs directly (after {sender} / {data} template substitution) without any destination validation. CCIP Read is enabled by default (global_ccip_read_enabled = True on all providers), meaning any application using web3.py's .call() method is exposed without explicit opt-in. This results in Server-Side Request Forgery (SSRF) when web3.py is used in backend services, indexers, APIs, or any environment that performs eth_call / .call() against untrusted or user-supplied contract addresses. A malicious contract can force the web3.py process to issue HTTP requests to arbitrary destinations, including internal network services and cloud metadata endpoints. This vulnerability is fixed in 7.15.0 and 8.0.0b2.