CVE-2019-18801
CVSS v3
9.8
CRITICAL
EPSS Score
2.5 %
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. An untrusted remote client may send HTTP/2 requests that write to the heap outside of the request buffers when the upstream is HTTP/1. This may be used to corrupt nearby heap contents (leading to a query-of-death scenario) or may be used to bypass Envoy's access control mechanisms such as path based routing. An attacker can also modify requests from other users that happen to be proximal temporally and spatially.
Technical details
- Published
- 2019-12-13
Frequently asked questions
What is CVE-2019-18801?
An 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 when the upstream is HTTP/1. This may be used to corrupt nearby heap contents (leading to a query-of-death scenario) or may be used to bypass Envoy's access control mechanisms such as path based routing. An attacker can also modify requests from other users that happen to be proximal temporally and spatially.
Is CVE-2019-18801 actively exploited?
Active exploitation of CVE-2019-18801 has not been confirmed. Its EPSS score was 2.5% on 2026-09-25, the estimated probability of exploitation in the next 30 days.
What is the CVSS score for CVE-2019-18801?
CVE-2019-18801 has a CVSS v3 base score of 9.8 (CRITICAL severity).
Is CVE-2019-18801 affecting your environment?
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