CVE-2019-18838

Name: CVE-2019-18838
Creator: NVD / NIST
Published: 2019-12-13T13:15:11.443+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 2.14%

Last modified Jun 17, 2026

CVE-2019-18838 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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. EPSS estimates a 2.14% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

7.5/10

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

EPSS Probability

2.14%

79.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-476

Affected Software

Vendor	Product	Versions
Envoyproxy	Envoy	<= 1.12.1

References

https://blog.envoyproxy.ioProduct
https://github.com/envoyproxy/envoy/commits/masterPatch
https://github.com/envoyproxy/envoy/security/advisories/GHSA-f2rv-4w6x-rwhcExploit, Third Party Advisory
https://groups.google.com/forum/#%21forum/envoy-users
https://blog.envoyproxy.ioProduct
https://github.com/envoyproxy/envoy/commits/masterPatch
https://github.com/envoyproxy/envoy/security/advisories/GHSA-f2rv-4w6x-rwhcExploit, Third Party Advisory
https://groups.google.com/forum/#%21forum/envoy-users

Timeline

Published: Dec 13, 2019
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2019-18838?

How severe is CVE-2019-18838?

CVE-2019-18838 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 2.14% probability of exploitation in the next 30 days.

How do I fix CVE-2019-18838?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2019-18838?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST