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Fencer Vulns
critical 9.8

CVE-2019-18801 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-2019-8506

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 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.

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

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-2019-18801 updated cvss 8.1

envoy: 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

  • 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

2.50% 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-gxvv-x4p2-rppp 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

Classification

Weakness

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.