{"cve":"CVE-2023-54397","nvd":{"published":"2026-09-15T16:17:05.777","modified":"2026-09-17T15:16:39.103","status":"Deferred","description":"Tornado before 6.3.3 contains an HTTP request smuggling vulnerability due to improper parsing of Content-Length headers accepting non-standard characters. Attackers can send crafted HTTP requests with these characters to bypass proxy validation and smuggle requests when deployed behind certain proxies.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:L/SI:H/SA:N","score":9.0},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:N","score":7.5},"cwes":["CWE-444"],"references":["https://github.com/tornadoweb/tornado/security/advisories/GHSA-qppv-j76h-2rpx","https://www.vulncheck.com/advisories/tornado-before-6.3.3-http-request-smuggling-via-content-length"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:53:43.293028046+00:00"},"epss":{"cve":"CVE-2023-54397","score":0.00377,"percentile":0.31725,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-qppv-j76h-2rpx","url":"https://osv.dev/vulnerability/GHSA-qppv-j76h-2rpx","summary":"Tornado vulnerable to HTTP request smuggling via improper parsing of `Content-Length` fields and chunk lengths","modified":"2026-09-16T03:56:01.387511075Z","packages":[{"ecosystem":"PyPI","name":"tornado","purl":"pkg:pypi/tornado","ranges":["<6.3.3"],"fixed":["6.3.3"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}