CNCF Envoy through 1.13.0 TLS inspector bypass.

published 2020-03-04 6 y ago modified 2026-09-08 2 mo ago also BIT-envoy-2020-8660 , EUVD-2020-29508 , GHSA-c4g8-7grc-5wvx

cvss: 5.3; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.6%; EPSS 0.6% chance of exploitation in 30 days, percentile 49%
public exploits: 0; none known

CNCF Envoy through 1.13.0 TLS inspector bypass. TLS inspector could have been bypassed (not recognized as a TLS client) by a client using only TLS 1.3. Because TLS extensions (SNI, ALPN) were not inspected, those connections might have been matched to a wrong filter chain, possibly bypassing some security restrictions in the process.

Patch / fix

fixed in 2 distros 1

bitnami envoy 1.12.3, 1.13.1
envoyproxy envoy 1.12.3, 1.13.1

servicemesh-proxy service mesh 1.0 1.0.9-2.el8

red hat advisories RHSA-2020:0734

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-8660 updated 2025-11-21 cvss 5.3

envoy: TLS inspector bypassc

Red Hat OpenShift Service Mesh 1.0 servicemesh-proxy 1.0.9-2.el8
fixed: vendor fix RHSA-2020:0734

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.61% chance of exploitation in the next 30 days, higher than 49% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
NVD	3.1	5.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
NVD	2.0	5.0	AV:N/AC:L/Au:N/C:P/I:N/A:N
OSV	3.1	5.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Affected packages

ecosystem	package	affected	fixed in
bitnami	envoy	<1.12.3 >=1.13.0, <1.13.1	1.12.3 1.13.1

Classification

Weakness

CWE-345 Insufficient Verification of Data Authenticity

References

access.redhat.com /errata/RHSA-2020:0734
vendor-advisory, third-party-advisory, advisory
envoyproxy.io /docs/envoy/v1.13.1/intro/version_history
vendor-advisory, advisory
github.com /envoyproxy/envoy/security/advisories/GHSA-c4g8-7grc-5wvx
third-party-advisory, advisory
nvd.nist.gov /vuln/detail/CVE-2020-8660
web

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary