{"cve":"CVE-2019-16254","nvd":{"published":"2019-11-26T18:15:15.210","modified":"2026-06-17T02:22:00.470","status":"Modified","description":"Ruby through 2.4.7, 2.5.x through 2.5.6, and 2.6.x through 2.6.4 allows HTTP Response Splitting. If a program using WEBrick inserts untrusted input into the response header, an attacker can exploit it to insert a newline character to split a header, and inject malicious content to deceive clients. NOTE: this issue exists because of an incomplete fix for CVE-2017-17742, which addressed the CRLF vector, but did not address an isolated CR or an isolated LF.","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:L/A:N","score":5.3},"cwes":["CWE-74"],"references":["http://lists.opensuse.org/opensuse-security-announce/2020-03/msg00041.html","https://hackerone.com/reports/331984","https://lists.debian.org/debian-lts-announce/2019/11/msg00025.html","https://lists.debian.org/debian-lts-announce/2019/12/msg00009.html","https://lists.debian.org/debian-lts-announce/2020/08/msg00027.html"],"products":["debian:debian_linux","ruby-lang:ruby"],"source":"nvd","synced_at":"2026-10-19T20:59:27.069234358+00:00"},"epss":{"cve":"CVE-2019-16254","score":0.04569,"percentile":0.91613,"date":"2026-10-31"},"kev":null,"osv":[],"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."]}