{"id":"CVE-2019-9900","aliases":["EUVD-2019-19256","GHSA-h9r7-c397-3wqr","GHSA-x74r-f4mw-c32h","RHSA-2019:0741"],"status":"published","title":"When parsing HTTP/1.x header values, Envoy 1.9.0 and before does not reject embedded zero...","description":"When parsing HTTP/1.x header values, Envoy 1.9.0 and before does not reject embedded zero characters (NUL, ASCII 0x0). This allows remote attackers crafting header values containing embedded NUL characters to potentially bypass header matching rules, gaining access to unauthorized resources.","severity":{"version":"3.0","score":6.5,"vector":"CVSS:3.0/AC:H/AV:N/A:L/C:L/I:L/PR:N/S:C/UI:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.03732,"percentile":0.89906,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-20","CWE-74"],"published":"2019-04-25T14:55:57Z","modified":"2026-10-20T10:50:57Z","affected":[{"source":"osv","ecosystem":"Red Hat:service_mesh:0","package":"servicemesh-proxy","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0:0.9.1-1.el7"}]}],"bundled":2}],"products":[{"vendor":"envoyproxy","product":"envoy"},{"vendor":"redhat","product":"openshift_service_mesh"}],"references":[{"url":"https://access.redhat.com/errata/RHSA-2019:0741","tags":["vendor-advisory","x_refsource_REDHAT","x_transferred","Third Party Advisory","advisory"]},{"url":"https://www.envoyproxy.io/docs/envoy/v1.9.1/intro/version_history","tags":["x_refsource_CONFIRM","x_transferred","Release Notes","Vendor Advisory","advisory"]},{"url":"https://github.com/envoyproxy/envoy/issues/6434","tags":["x_refsource_CONFIRM","x_transferred","Exploit","Issue Tracking","Third Party Advisory","report"]},{"url":"https://groups.google.com/forum/#%21topic/envoy-announce/VoHfnDqZiAM","tags":["x_refsource_CONFIRM","x_transferred","web"]},{"url":"https://github.com/envoyproxy/envoy/security/advisories/GHSA-x74r-f4mw-c32h","tags":["x_refsource_CONFIRM","x_transferred","Exploit","Mitigation","Third Party Advisory","evidence"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2019-9900","tags":["advisory"]},{"url":"https://groups.google.com/forum/#!topic/envoy-announce/VoHfnDqZiAM"},{"url":"https://github.com/advisories/GHSA-h9r7-c397-3wqr"},{"url":"https://access.redhat.com/security/updates/classification/#important","tags":["article"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=1698020","tags":["report"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=1698025","tags":["report"]},{"url":"https://security.access.redhat.com/data/csaf/v2/advisories/2019/rhsa-2019_0741.json","tags":["advisory"]},{"url":"https://access.redhat.com/security/cve/CVE-2019-9900","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2019-9900","tags":["advisory"]},{"url":"https://access.redhat.com/security/cve/CVE-2019-9901","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2019-9901","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2019-9901","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2019-9900","description":"When parsing HTTP/1.x header values, Envoy 1.9.0 and before does not reject embedded zero characters (NUL, ASCII 0x0). This allows remote attackers crafting header values containing embedded NUL characters to potentially bypass header matching rules, gaining access to unauthorized resources.","status":"published","published":"2019-04-25T14:55:57Z","modified":"2024-08-04T22:01:55.177Z","cvss":[{"version":"3.0","score":6.5,"vector":"CVSS:3.0/AC:H/AV:N/A:L/C:L/I:L/PR:N/S:C/UI:N","level":"medium","assessor":"cna"}],"updated_at":"2026-11-02T14:20:20.397093Z"}],"euvd":[{"id":"EUVD-2019-19256","description":"When parsing HTTP/1.x header values, Envoy 1.9.0 and before does not reject embedded zero characters (NUL, ASCII 0x0). This allows remote attackers crafting header values containing embedded NUL characters to potentially bypass header matching rules, gaining access to unauthorized resources.","status":"published","published":"2019-04-25T14:55:57Z","modified":"2024-08-04T22:01:55Z","cvss":[{"version":"3.0","score":6.5,"vector":"CVSS:3.0/AC:H/AV:N/A:L/C:L/I:L/PR:N/S:C/UI:N","level":"medium"}],"updated_at":"2026-11-03T02:40:54.59684Z"}],"ghsa":[{"id":"GHSA-h9r7-c397-3wqr","title":"When parsing HTTP/1.x header values, Envoy 1.9.0 and before does not reject embedded zero...","description":"When parsing HTTP/1.x header values, Envoy 1.9.0 and before does not reject embedded zero characters (NUL, ASCII 0x0). This allows remote attackers crafting header values containing embedded NUL characters to potentially bypass header matching rules, gaining access to unauthorized resources.","status":"published","published":"2022-05-24T16:44:38Z","modified":"2024-04-04T00:06:37Z","cvss":[{"version":"3.1","score":8.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L","level":"high"}],"cwes":["CWE-20","CWE-74"],"updated_at":"2026-11-02T14:55:49.472376Z"}],"nvd":[{"id":"CVE-2019-9900","description":"When parsing HTTP/1.x header values, Envoy 1.9.0 and before does not reject embedded zero characters (NUL, ASCII 0x0). This allows remote attackers crafting header values containing embedded NUL characters to potentially bypass header matching rules, gaining access to unauthorized resources.","status":"published","published":"2019-04-25T15:29:01.497Z","modified":"2026-06-17T02:44:48.977Z","cvss":[{"version":"3.1","score":8.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L","level":"high","assessor":"primary"},{"version":"3.0","score":6.5,"vector":"CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:L","level":"medium","assessor":"secondary"},{"version":"2.0","score":7.5,"vector":"AV:N/AC:L/Au:N/C:P/I:P/A:P","level":"high","assessor":"primary"}],"cwes":["CWE-74"],"updated_at":"2026-11-02T14:05:12.471695Z"}],"osv":[{"id":"CVE-2019-9900","description":"When parsing HTTP/1.x header values, Envoy 1.9.0 and before does not reject embedded zero characters (NUL, ASCII 0x0). This allows remote attackers crafting header values containing embedded NUL characters to potentially bypass header matching rules, gaining access to unauthorized resources.","status":"published","published":"2019-04-25T15:29:01.497Z","modified":"2026-10-20T10:50:57.647828364Z","cvss":[{"version":"3.1","score":8.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L","level":"high"}],"updated_at":"2026-11-02T15:44:13.492058Z"},{"id":"RHSA-2019:0741","title":"Red Hat Security Advisory: Istio-Proxy Security Update","status":"published","published":"2024-09-16T02:22:51Z","modified":"2026-03-18T11:30:37.836217Z","cvss":[{"version":"3.0","score":8.3,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L","level":"high"}],"updated_at":"2026-11-02T15:53:05.383061Z"}]}}