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

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

6.9 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N · score source

EPSS

• CVE-2026-111171: 0.34% estimated exploitation activity in the next 30 days; percentile 27.70 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
• CVE-2026-40072: 0.23% estimated exploitation activity in the next 30 days; percentile 13.72 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary web3.py implements CCIP Read / OffchainLookup (EIP-3668) by performing HTTP requests to URLs supplied by smart contracts in offchainlookuppayload["urls"]. The implementation uses these contract-supplied URLs directly (after {sender} / {data} template substitution) without any destination validation: - No restriction to https:// (and no opt-in gate for http://) - No hostname or IP allowlist - No blocking of private/reserved IP ranges (loopback, link-local, RFC1918) - No redirect target validation (both requests and aiohttp follow redirects by default) CCIP Read is enabled by default (globalccipreadenabled = 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 ethcall / .call() against untrusted or user-supplied contract addresses. A malicious contract can force the web3.py…

Published by the source

4 Apr 2026, 06:38 UTC

Last modified by the source

16 Oct 2026, 10:55 UTC

Source last checked

26 Oct 2026, 13:45 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-5hr4-253g-cpx2

2. Revision 2 · amended · 25 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-5hr4-253g-cpx2

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# Patch Next advisory brief: CVE-2026-111171

Advisory: web3.py: SSRF via CCIP Read (EIP-3668) OffchainLookup URL handling
IDs: CVE-2026-111171, GHSA-5hr4-253g-cpx2
Record: https://patchnext.com/advisories/cve-2026-111171 (revision 3, source checked 26 Oct 2026, 13:45 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: web3 8.0.0b2, 7.15.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI web3: affected >= 6.0.0b3, < 7.15.0; >= 8.0.0b1, <= 8.0.0b1; fixed in 8.0.0b2, 7.15.0

## Suggested inspection (read-only)
- `python -m pip show web3`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on web3.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-5hr4-253g-cpx2 (OSV record GHSA-5hr4-253g-cpx2 lists affected ranges: PyPI web3 >=6.0.0b3 =8.0.0b1 <8.0.0b2 (fixed))
- Verified: https://github.com/advisories/GHSA-5hr4-253g-cpx2 (GitHub-reviewed advisory GHSA-5hr4-253g-cpx2 lists affected ranges: PyPI web3 >=6.0.0b3 =8.0.0b1 <=8.0.0b1)

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