---
id: CVE-2026-111171
title: >-
  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
summary: >-
  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 retu…
severity: medium
cvss: 5.4
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N'
cwe:
  - CWE-918
vendor: ethereum
product: web3.py
affected:
  - web3.py >= 7.15.0 <= 7.16.0
  - web3.py >= 8.0.0b2 <= 8.0.0
patched:
  - web3 7.15.0
  - web3 8.0.0b2
published: '2026-10-15'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T18:25:45.343'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-111171'
references:
  - url: 'https://github.com/ethereum/web3.py'
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/ethereum/web3.py/blob/c8c1ed0c9e77e1a8b74902e6a6825e0b00534b10/web3/utils/ccip_url_validation.py#L16-L57
    label: disclosure@vulncheck.com
  - url: 'https://github.com/ethereum/web3.py/pull/3875'
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/ethereum/web3.py/security/advisories/GHSA-5hr4-253g-cpx2
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/web3-py-7.15.0-through-7.16.0-and-8.0-0b2-through-8.0.0-ccip-read-ssrf-bypass
    label: disclosure@vulncheck.com
  - url: 'https://github.com/ApeWorX/web3.py/security/advisories/GHSA-5hr4-253g-cpx2'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-40072'
  - url: >-
      https://github.com/ethereum/web3.py/commit/b1c57bb0a124359c9902daaefab4d8af7c3c4c1e
  - url: 'https://pypi.org/project/web3'
  - url: 'https://github.com/advisories/GHSA-5hr4-253g-cpx2'
tags:
  - nvd
  - cve.org
  - exploit-available
  - osv
  - pip
epss: 0.00341
epssPercentile: 0.27464
aliases:
  - GHSA-5hr4-253g-cpx2
  - CVE-2026-40072
  - PYSEC-2026-3414
ecosystem: pip
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-15T19:29:17.459655Z'
scores:
  nvd: 5.4
  osv: 7.2
ingestedAt: '2026-10-15T19:25:46.425Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-111171)

Affected packages:

- `web3 >= 6.0.0b3, < 7.15.0`
- `web3 >= 8.0.0b1, < 8.0.0b2`

Patched in:

- `web3 7.15.0`
- `web3 8.0.0b2`

Source: https://osv.dev/vulnerability/GHSA-5hr4-253g-cpx2