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Fencer Vulns
critical 9.8

CVE-2019-18802 json

An issue was discovered in Envoy 1.12.0.

published 2019-12-13 6 y ago modified 2026-06-17 4 mo ago also EUVD-2019-8507

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.5%
EPSS 2.5% chance of exploitation in 30 days, percentile 84%
public exploits
0
none known

Summary

An issue was discovered in Envoy 1.12.0. An untrusted remote client may send an HTTP header (such as Host) with whitespace after the header content. Envoy will treat "header-value " as a different string from "header-value" so for example with the Host header "example.com " one could bypass "example.com" matchers.

Patch / fix

  • kiali service mesh 1.0 v1.0.8.redhat1-1.el7
  • servicemesh service mesh 1.0 1.0.3-1.el8
  • servicemesh-cni service mesh 1.0 1.0.3-1.el8
  • servicemesh-mixc service mesh 1.0 1.0.3-1.el8
  • servicemesh-mixs service mesh 1.0 1.0.3-1.el8
  • servicemesh-proxy service mesh 1.0 1.0.3-1.el8
  • servicemesh-galley service mesh 1.0 1.0.3-1.el8
  • servicemesh-citadel service mesh 1.0 1.0.3-1.el8

red hat advisories RHSA-2019:4222

  • nghttp2 SLE Module for Basesystem 15 SP1 1.40.0-3.6.3

suse advisories SUSE-SU-2020:0722-1

  • nghttp2 openSUSE Tumbleweed 1.64.0-1.1
  • nghttp2 openSUSE Leap 15.2 1.40.0-lp152.2.3.1
  • nghttp2-python openSUSE Leap 15.2 1.40.0-lp152.2.3.1
  • nghttp2 openSUSE Leap 15.1 1.40.0-lp151.3.6.1
  • nghttp2-python openSUSE Leap 15.1 1.40.0-lp151.3.6.1

opensuse advisories openSUSE-SU-2024:14491-1openSUSE-SU-2021:0341-1openSUSE-SU-2020:0379-1

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-2019-18802 updated cvss 7.5

envoy: malformed request header may cause bypass of route matchers resulting in escalation of privileges or information disclosure

  • Red Hat OpenShift Service Mesh 1.0 servicemesh 1.0.3-1.el8, servicemesh-cni 1.0.3-1.el8, servicemesh-mixc 1.0.3-1.el8, servicemesh-mixs 1.0.3-1.el8, servicemesh-proxy 1.0.3-1.el8, servicemesh-galley 1.0.3-1.el8, +9 more Red Hat OpenShift Service Mesh 1.0 kiali v1.0.8.redhat1-1.el7
    fixed: vendor fix RHSA-2019:4222

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

2.46% chance of exploitation in the next 30 days, higher than 84% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/envoyproxy/envoy/security/advisories/GHSA-356m-vhw2-wcm4 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

References

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.