{"cve":"CVE-2019-18838","nvd":{"published":"2019-12-13T13:15:11.443","modified":"2026-06-17T02:25:26.567","status":"Modified","description":"An issue was discovered in Envoy 1.12.0. Upon receipt of a malformed HTTP request without a Host header, it sends an internally generated \"Invalid request\" response. This internally generated response is dispatched through the configured encoder filter chain before being sent to the client. An encoder filter that invokes route manager APIs that access a request's Host header causes a NULL pointer dereference, resulting in abnormal termination of the Envoy process.","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:N/A:H","score":7.5},"cwes":["CWE-476"],"references":["https://blog.envoyproxy.io","https://github.com/envoyproxy/envoy/commits/master","https://github.com/envoyproxy/envoy/security/advisories/GHSA-f2rv-4w6x-rwhc","https://groups.google.com/forum/#%21forum/envoy-users","https://blog.envoyproxy.io"],"products":["envoyproxy:envoy"],"source":"nvd","synced_at":"2026-10-19T20:59:27.069234358+00:00"},"epss":{"cve":"CVE-2019-18838","score":0.02142,"percentile":0.82064,"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."]}