CVE-2019-18801

Name: CVE-2019-18801
Creator: NVD / NIST
Published: 2019-12-13T13:15:11.303+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 2.50%

Last modified Jun 17, 2026

CVE-2019-18801 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. 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. EPSS estimates a 2.50% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

2.50%

82.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-787

Affected Software

Vendor	Product	Versions
Envoyproxy	Envoy	<= 1.12.1

References

https://access.redhat.com/errata/RHSA-2019:4222Third Party Advisory
https://blog.envoyproxy.ioProduct
https://github.com/envoyproxy/envoy/commits/masterPatch
https://github.com/envoyproxy/envoy/security/advisories/GHSA-gxvv-x4p2-rpppExploit, Third Party Advisory
https://groups.google.com/forum/#%21forum/envoy-users
https://access.redhat.com/errata/RHSA-2019:4222Third Party Advisory
https://blog.envoyproxy.ioProduct
https://github.com/envoyproxy/envoy/commits/masterPatch
https://github.com/envoyproxy/envoy/security/advisories/GHSA-gxvv-x4p2-rpppExploit, 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-2019-18801?

How severe is CVE-2019-18801?

CVE-2019-18801 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 2.50% probability of exploitation in the next 30 days.

How do I fix CVE-2019-18801?

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-2019-18801?

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

Scan your code now

Source: NVD / NIST