high CVSS 7.2

CVE-2026-40072·Python vulnerability

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.

Severity
high
Software
Python
Fixed in
7.15.0
Published
2026-04-09

Affected versions

From: 6.1.0

Until: 7.15.0

Fixed in: 7.15.0

How to fix this CVE

Update web3.py to version 7.15.0 or later to patch an SSRF vulnerability that allows malicious smart contracts to trigger arbitrary HTTP requests from your Python environment. This vulnerability affects all applications using web3.py's .call() method against untrusted contracts, particularly backend services, indexers, and APIs. Upgrade immediately and consider disabling CCIP Read globally if you cannot update immediately by setting global_ccip_read_enabled = False in your provider configuration.

sudo dnf upgrade python3-web3 || sudo pip3 install --upgrade web3>=7.15.0

Defensia detects this vulnerability

How to check if you are affected

  1. Check installed web3.py version: pip3 show web3 | grep Version
  2. Verify vulnerable versions are present: python3 -c "import web3; print(web3.__version__)" and confirm it falls between 6.1.0 and 7.14.x
  3. Search application logs for unexpected HTTP requests to internal IPs or cloud metadata endpoints (169.254.169.254, localhost, 10.0.0.0/8): grep -r 'HTTP.*GET.*169.254\|localhost\|10\.0' /var/log/
  4. Confirm the patch by running: python3 -c "import web3; assert web3.__version__ >= '7.15.0', 'Vulnerable version'; print('Patched')"

FAQ

What is CVE-2026-40072?

CVE-2026-40072 is a Server-Side Request Forgery (SSRF) vulnerability in web3.py that allows malicious Ethereum smart contracts to force the Python process to make HTTP requests to arbitrary internal network destinations, including cloud metadata endpoints and internal services.

Is CVE-2026-40072 being actively exploited?

No, CVE-2026-40072 is not currently listed in CISA's Known Exploited Vulnerabilities catalog and no public exploits are available, though the vulnerability is trivial to exploit by deploying a malicious contract.

What versions of Python are affected by CVE-2026-40072?

The vulnerability affects web3.py versions 6.1.0 through 7.14.x. The affected component is web3.py, not Python itself. Fixed versions are 7.15.0 and 8.0.0b2 or later.

How do I check if my server is vulnerable to CVE-2026-40072?

Run 'pip3 show web3' and check the Version field; if it is between 6.1.0 and 7.14.x, your system is vulnerable. Then verify your application calls web3.py's .call() method against untrusted contract addresses.

Does Defensia detect CVE-2026-40072?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If web3.py is installed on a monitored server, CVE-2026-40072 will appear in your dashboard with remediation steps.

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References

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