← Vulnerability feed

Vulnerability record · CVE-2019-18802 · published 13 December 2019

CVE-2019-18802: Envoyproxy envoy vulnerability

Envoyproxy · Envoy

An issue was discovered in Envoy 1.12.0. An untrusted remote client may send an HTTP header (such as Host) with whitespace after the header content. Envoy will treat "header-value " as a different string from "header-value" so for example with the Host header "example.com " one could bypass "example.com" matchers.

9.8 CVSS 3.1 Critical EPSS 2.5% · top 16.2%
9.8CVSS 3.1 base score, v2 7.5
2.5%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
10References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

An issue was discovered in Envoy 1.12.0. An untrusted remote client may send an HTTP header (such as Host) with whitespace after the header content. Envoy will treat "header-value " as a different string from "header-value" so for example with the Host header "example.com " one could bypass "example.com" matchers.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://lists.opensuse.org/opensuse-security-announce/2020-03/msg00034.html
https://blog.envoyproxy.io Product
https://github.com/envoyproxy/envoy/commits/master Patch
https://github.com/envoyproxy/envoy/security/advisories/GHSA-356m-vhw2-wcm4 ExploitThird Party Advisory
https://groups.google.com/forum/#%21forum/envoy-users
http://lists.opensuse.org/opensuse-security-announce/2020-03/msg00034.html
https://blog.envoyproxy.io Product
https://github.com/envoyproxy/envoy/commits/master Patch
https://github.com/envoyproxy/envoy/security/advisories/GHSA-356m-vhw2-wcm4 ExploitThird Party Advisory
https://groups.google.com/forum/#%21forum/envoy-users

Track CVE-2019-18802 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

7.5CVE-2023-44487HTTP/2 Rapid Reset stream cancellation denial of serviceThe HTTP/2 protocol permits a client to cancel many streams quickly, and the server's handling of those resets consumes disproportionate resources. T…KEVEPSS 100%analysed10.0CVE-2019-9901Envoyproxy envoy vulnerabilityEnvoy 1.9.0 and before does not normalize HTTP URL paths. A remote attacker may craft a relative path, e.g., something/../admin, to bypass access con…EPSS 5.0%9.8CVE-2023-35941Envoyproxy envoy vulnerabilityEnvoy is an open source edge and service proxy designed for cloud-native applications. Prior to versions 1.27.0, 1.26.4, 1.25.9, 1.24.10, and 1.23.12…EPSS 0.81%9.8CVE-2023-27488Envoyproxy envoy improper input validation vulnerabilityEnvoy is an open source edge and service proxy designed for cloud-native applications. Prior to versions 1.26.0, 1.25.3, 1.24.4, 1.23.6, and 1.22.9, …EPSS 0.73%9.8CVE-2022-21654Envoyproxy envoy improper certificate validation vulnerabilityEnvoy is an open source edge and service proxy, designed for cloud-native applications. Envoy's tls allows re-use when some cert validation settings …EPSS 1.1%9.8CVE-2019-18801Envoyproxy envoy out-of-bounds write vulnerabilityAn issue was discovered in Envoy 1.12.0. An untrusted remote client may send HTTP/2 requests that write to the heap outside of the request buffers wh…EPSS 2.5%9.1CVE-2024-39305Envoyproxy envoy use after free vulnerabilityEnvoy is a cloud-native, open source edge and service proxy. Prior to versions 1.30.4, 1.29.7, 1.28.5, and 1.27.7. Envoy references already freed mem…EPSS 0.65%9.1CVE-2023-27493Envoyproxy envoy improper input validation vulnerabilityEnvoy is an open source edge and service proxy designed for cloud-native applications. Prior to versions 1.26.0, 1.25.3, 1.24.4, 1.23.6, and 1.22.9, …EPSS 0.51%

Source: NIST National Vulnerability Database (record CVE-2019-18802), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.