Ethereum Web3.py up to 7.16.0/8.0.0 CCIP Read URL Validation _check_ip_blocked server-side request forgery

Summaryinfo

A vulnerability, which was classified as critical, has been found in Ethereum Web3.py up to 7.16.0/8.0.0. This impacts the function _check_ip_blocked of the component CCIP Read URL Validation. The manipulation leads to server-side request forgery. This vulnerability is traded as CVE-2026-111171. It is possible to initiate the attack remotely. There is no exploit available.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Ethereum Web3.py up to 7.16.0/8.0.0. This issue affects the function _check_ip_blocked of the component CCIP Read URL Validation. The manipulation with an unknown input leads to a server-side request forgery vulnerability. Using CWE to declare the problem leads to CWE-918. The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-111171 since 10/15/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 10/15/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Vendor

• Ethereum

Name

• Web3.py

Version

• 7.0
• 7.1
• 7.2
• 7.3
• 7.4
• 7.5
• 7.6
• 7.7
• 7.8
• 7.9
• 7.10
• 7.11
• 7.12
• 7.13
• 7.14
• 7.15
• 7.16.0
• 8.0

Website

• Product: https://github.com/ethereum/web3.py/

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