{"cve":"CVE-2020-5207","nvd":{"published":"2020-01-27T20:15:10.980","modified":"2026-06-17T03:21:01.517","status":"Modified","description":"In Ktor before 1.3.0, request smuggling is possible when running behind a proxy that doesn't handle Content-Length and Transfer-Encoding properly or doesn't handle \\n as a headers separator.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","score":7.5},"cwes":["CWE-444"],"references":["https://github.com/ktorio/ktor/pull/1547","https://github.com/ktorio/ktor/security/advisories/GHSA-xrr9-rh8p-433v","https://github.com/ktorio/ktor/pull/1547","https://github.com/ktorio/ktor/security/advisories/GHSA-xrr9-rh8p-433v"],"products":["jetbrains:ktor"],"source":"nvd","synced_at":"2026-10-19T21:01:01.339895972+00:00"},"epss":{"cve":"CVE-2020-5207","score":0.00762,"percentile":0.55381,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-xrr9-rh8p-433v","url":"https://osv.dev/vulnerability/GHSA-xrr9-rh8p-433v","summary":"Request smuggling is possible when both chunked TE and content length specified","modified":"2026-07-08T05:59:54.373628390Z","packages":[{"ecosystem":"Maven","name":"io.ktor:ktor-client-cio","purl":"pkg:maven/io.ktor/ktor-client-cio","ranges":["<1.3.0"],"fixed":["1.3.0"]},{"ecosystem":"Maven","name":"io.ktor:ktor-server-cio","purl":"pkg:maven/io.ktor/ktor-server-cio","ranges":["<1.3.0"],"fixed":["1.3.0"]}]}],"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."]}