CVE-2019-18838
CVSS v3
7.5
HIGH
EPSS Score
2.1 %
exploit probability, as of 2026-09-25
CISA KEV
No
known exploited
Exploitation
—
SSVC status
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.
Technical details
- Published
- 2019-12-13
Frequently asked questions
What is CVE-2019-18838?
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.
Is CVE-2019-18838 actively exploited?
Active exploitation of CVE-2019-18838 has not been confirmed. Its EPSS score was 2.1% on 2026-09-25, the estimated probability of exploitation in the next 30 days.
What is the CVSS score for CVE-2019-18838?
CVE-2019-18838 has a CVSS v3 base score of 7.5 (HIGH severity).
Is CVE-2019-18838 affecting your environment?
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