What’s Vulnerable › Vulnerabilities

CVE-2019-18802

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.5% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2019-12-13 · updated 2026-06-17

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.

Affected products

• envoyproxy envoy: through 1.12.1

References

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

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