CVE-2026-40072

web3.py affected by SSRF via CCIP Read (EIP-3668) OffchainLookup URL handling

Published Apr 9, 2026 CVSS 4.0 · 1.7 Low EPSS < 1% KEV · Not listed

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.

Analysis

Technical impact

The vulnerability stems from web3.py’s handling of the CCIP Read/OffchainLookup mechanism as defined by EIP‑3668. The library performs HTTP requests to URLs supplied by a smart contract without validating the destination, allowing an attacker to supply arbitrary URLs. This missing validation results in a Server‑Side Request Forgery that can be leveraged from any backend process that uses the library’s .call() method. The flaw can expose internal network resources or cloud metadata services to attackers through the library.

Affected Systems

The affected library is Ethereum’s web3.py. Versions starting with 6.0.0b3 up to but excluding 7.15.0 and including 8.0.0b2 are vulnerable. All providers have CCIP Read enabled by default, so any application that uses .call() with untrusted or user‑supplied contract addresses is at risk.

Risk and Exploitability

The CVSS score of 1.7 indicates a low‑severity flaw, and no EPSS information is available; the vulnerability is not listed in the CISA KEV catalog. The likely attack path involves a malicious smart contract returning an offchain_lookup_payload containing crafted URLs, causing a backend service running web3.py to issue requests to arbitrary endpoints. Because the library performs the calls automatically, no additional user interaction is required other than the execution of .call() against the contract. The lack of destination validation makes exploitation straightforward for an attacker who can control the contract data.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

ethereum

web3.py

affected

Version	Status	Constraints
`>= 6.0.0b3, < 7.15.0`	affected	—
`>= 8.0.0b1, < 8.0.0b2`	affected	—

Configuration 1 [-]

OR	cpe:2.3:a:apeworx:web3.py::::::python::*
	cpe:2.3:a:apeworx:web3.py:6.0.0:-::::python::*
	cpe:2.3:a:apeworx:web3.py:6.0.0:beta10::::python::*
	cpe:2.3:a:apeworx:web3.py:6.0.0:beta11::::python::*
	cpe:2.3:a:apeworx:web3.py:6.0.0:beta3::::python::*
	cpe:2.3:a:apeworx:web3.py:6.0.0:beta4::::python::*
	cpe:2.3:a:apeworx:web3.py:6.0.0:beta5::::python::*
	cpe:2.3:a:apeworx:web3.py:6.0.0:beta6::::python::*
	cpe:2.3:a:apeworx:web3.py:6.0.0:beta7::::python::*
	cpe:2.3:a:apeworx:web3.py:6.0.0:beta8::::python::*
	cpe:2.3:a:apeworx:web3.py:6.0.0:beta9::::python::*
	cpe:2.3:a:apeworx:web3.py:8.0.0:beta1::::python::*

No data.

Vendor Product Versions

Ethereum

Web3.py

Version	Status	Scheme	Platform
`[6.0.0b3,7.15.0)`	affected	generic	—
`[8.0.0b1,8.0.0b2)`	affected	generic	—

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Upgrade web3.py to version 7.15.0 or 8.0.0b2 to apply the vendor fix.
If upgrading is not immediately possible, disable global CCIP Read by setting global_ccip_read_enabled=False or configuring the provider to forbid offchain lookup.
Avoid calling .call() on contracts whose source is not trusted or that could return an offchain_lookup_payload.
Monitor outbound HTTP traffic from backend services for unexpected or suspicious requests to internal or cloud metadata endpoints.

Generated by OpenCVE AI on April 9, 2026 at 19:21 UTC.

Tracking

Advisories

Source	ID	Title
Github GHSA	GHSA-5hr4-253g-cpx2	web3.py: SSRF via CCIP Read (EIP-3668) OffchainLookup URL handling

Metrics

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements Present

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact Low

Subsequent System Integrity Impact Low

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Changed

Confidentiality Impact Low

Integrity Impact Low

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.237% probability within 30 days)

Exploitation poc

Automatable no

Technical Impact partial

References

Link	Providers
https://github.com/ethereum/web3.py/commit/b1c57bb0a124359c9902daaefab4d8af7c3c4c1e
https://github.com/ethereum/web3.py/security/advisories/GHSA-5hr4-253g-cpx2

History

Jun 2, 2026 5:00 PM First appearance in the feed. Affected versions updated. Affected vendors updated. Scoring metrics updated View changes

Type	Values Removed	Values Added
First Time appeared		Apeworx Apeworx web3.py
CPEs		cpe:2.3:a:apeworx:web3.py::::::python::* cpe:2.3:a:apeworx:web3.py:6.0.0:-::::python::* cpe:2.3:a:apeworx:web3.py:6.0.0:beta10::::python::* cpe:2.3:a:apeworx:web3.py:6.0.0:beta11::::python::* cpe:2.3:a:apeworx:web3.py:6.0.0:beta3::::python::* cpe:2.3:a:apeworx:web3.py:6.0.0:beta4::::python::* cpe:2.3:a:apeworx:web3.py:6.0.0:beta5::::python::* cpe:2.3:a:apeworx:web3.py:6.0.0:beta6::::python::* cpe:2.3:a:apeworx:web3.py:6.0.0:beta7::::python::* cpe:2.3:a:apeworx:web3.py:6.0.0:beta8::::python::* cpe:2.3:a:apeworx:web3.py:6.0.0:beta9::::python::* cpe:2.3:a:apeworx:web3.py:8.0.0:beta1::::python::*
Vendors & Products		Apeworx Apeworx web3.py
Metrics		cvssV3_1 `{'score': 7.2, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N'}`

Apr 10, 2026 9:00 AM First appearance in the feed. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Ethereum Ethereum web3.py
Vendors & Products		Ethereum Ethereum web3.py

Apr 10, 2026 4:15 AM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Apr 9, 2026 6:00 PM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
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.
Title		web3.py affected by SSRF via CCIP Read (EIP-3668) OffchainLookup URL handling
Weaknesses		CWE-918
References		https://github.com/ethereum/web3.py/commit/b1c57bb0a124359c9902daaefab4d8af7c3c4c1e https://github.com/ethereum/web3.py/security/advisories/GHSA-5hr4-253g-cpx2
Metrics		cvssV4_0 `{'score': 1.7, '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'}`