Vulnerability · CVE-2026-111171
Web3.py 7.15.0 through 7.16.0 and 8.0.0b2 through 8.0.0 CCIP-Read SSRF Bypass
Published Apr 4, 2026 · catalog updated Oct 16, 2026 · Web3.py 7.15.0 through 7.16.0
Check if you run it
No confirmed exploitation is on record for CVE-2026-111171. EPSS is 0.34%. Act only if a listed version of Web3.py 7.15.0 through 7.16.0 is installed.
Gaps on this record
- The stored product name is a package slug. The name on this page is taken from the title (Web3.py 7.15.0 through 7.16.0).
- No vendor fix or required action is stored. Compare the linked advisory before you change production.
- Severity
- High7.2
- Known exploitation
- Not in CISA/VulnCheck KEV
- EPSS
- 0.34%
- Remediation
- Advisory link
- Affected products
- PyPI web3 · vendor ethereum web3.py
## Summary web3.py implements CCIP Read / (EIP-3668) by performing HTTP requests to URLs supplied by smart contracts in . The implementation uses these contract-supplied URLs directly (after / template substitution) without any destination validation: - No restriction to (and no opt-in gate for ) - No hostname or IP allowlist - No blocking of private/reserved IP ranges (loopback, link-local, RFC1918) - No redirect target validation (both and follow redirects by default) **CCIP Read is enabled by default** ( on all providers), meaning any application using web3.py's 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 / 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. --- ## Why This Is a Vulnerability The argument is not that CCIP Read itself is invalid or that web3.py should stop supporting EIP-3668. The issue is that, in server-side deployments (backends, indexers, bots, APIs), the current implementation doesn't provide destination policy controls, such as a validation/override hook, private-range blocking, or redirect target checks, which means contract controlled CCIP URLs can be used as an SSRF primitive. This is consistent with EIP-3668's own security considerations, which recommends that client libraries "provide clients with a hook to override CCIP read calls, either by rewriting them to use a proxy service, or by denying them entirely" and that "this mechanism or another should be written so as to easily facilitate adding domains to allowlists or blocklists." The mitigations I'm suggesting are meant to align with that guidance without breaking CCIP Read support. - **Default-on exposure.** CCIP Read is enabled by default on all web3.py providers ( ). User
Are you affected?
Enter the version you run. The result uses only the ranges stored on this record.
The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.
- PyPI web36.0.0b3 → 7.15.0
- PyPI web38.0.0b1 → 8.0.0b2
- vendor ethereum web3.pyversion unspecified
How to fix CVE-2026-111171
Recommended remediation
A patch or advisory reference is linked. Open the original publisher for availability by product version.
Official advisories
What to do
Three questions, each answered from this record only. Confirm the vendor advisory before you patch.
Should you patch?
No confirmed exploitation is on record for CVE-2026-111171. EPSS is 0.34%. Act only if a listed version of Web3.py 7.15.0 through 7.16.0 is installed.
Which versions are affected?
Compare what you have installed with 6.0.0b3 → 7.15.0, 8.0.0b1 → 8.0.0b2. Compare the installed version with the linked vendor advisory before you change production.
What should an analyst verify?
CWE-918: Server-Side Request Forgery (SSRF). EPSS 0.34%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.
Code
The project this record applies to. Exploit listings stay in References.
Timeline
Detection, updates, and resolution for this record.
Oct 15, 2026 · NIST NVD
Detected
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 service
Oct 15, 2026 · CIRCL Vulnerability Lookup
Updated
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 service
Oct 16, 2026 · GitHub Advisory Database
Fix available
web3 fixed in 7.15.0; web3 fixed in 8.0.0b2
Oct 16, 2026 · GitHub Advisory Database
Fix available
web3 fixed in 7.15.0
Oct 16, 2026 · GitHub Advisory Database
Fix available
web3 fixed in 8.0.0b2
Oct 16, 2026 · GitHub Advisory Database
Fix available
web3 fixed in 7.15.0
Oct 16, 2026 · GitHub Advisory Database
Updated
## Summary web3.py implements CCIP Read / (EIP-3668) by performing HTTP requests to URLs supplied by smart contracts in . The implementation uses these contract-supplied URLs directly (after / template substitution) without any destination validation: - No restriction to (and no opt-in gate for ) - No hostname or IP allowlist - No blocking of private/reserved IP ranges (loopback, link-local, RFC19
Sources
- CIRCL Vulnerability LookupVulnerability recordCVE-2026-111171
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 IPv
vulnerability.circl.lu - CVE.orgVulnerability recordCVE-2026-111171
Official CVE identifier
cve.org - FIRST EPSSExploitation probabilityCVE-2026-111171
30-day exploitation probability 0.3%
first.org - GitHub Advisory DatabasePackage advisoryGHSA-5hr4-253g-cpx2
GitHub Advisory Database record mirrored by OSV.
github.com - NIST NVDVulnerability recordCVE-2026-111171
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 IPv
nvd.nist.gov - OpenSSF OSV / OSV ScannerPackage advisoryGHSA-5hr4-253g-cpx2
web3.py: SSRF via CCIP Read (EIP-3668) OffchainLookup URL handling
osv.dev - OpenSSF OSV / OSV ScannerPackage advisoryPYSEC-2026-3414
web3.py: SSRF via CCIP Read (EIP-3668) OffchainLookup URL handling
osv.dev - PyPA Advisory DatabasePackage advisoryGHSA-5hr4-253g-cpx2
web3.py: SSRF via CCIP Read (EIP-3668) OffchainLookup URL handling
osv.dev - PyPA Advisory DatabasePackage advisoryPYSEC-2026-3414
web3.py: SSRF via CCIP Read (EIP-3668) OffchainLookup URL handling
osv.dev
References
Freshness
Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.