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Fencer Vulns
high 7.5

CVE-2021-28682 json

An issue was discovered in Envoy through 1.71.1.

published 2021-05-20 5 y ago modified 2026-09-08 2 mo ago also BIT-envoy-2021-28682 , EUVD-2021-15339 , GHSA-r22g-5f3x-xjgg

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.0%
EPSS 2.0% chance of exploitation in 30 days, percentile 81%
public exploits
0
none known

Summary

An issue was discovered in Envoy through 1.71.1. There is a remotely exploitable integer overflow in which a very large grpc-timeout value leads to unexpected timeout calculations.

Patch / fix

  • bitnami envoy 1.14.7, 1.15.4, 1.16.3, 1.17.2
  • servicemesh-proxy service mesh 2.0 2.0.3-1.el8
  • servicemesh-proxy service mesh 1.1 1.1.13-1.el8
  • servicemesh-pilot-agent service mesh 1.1 1.1.13-3.el8
  • servicemesh-pilot-discovery service mesh 1.1 1.1.13-3.el8

red hat advisories RHSA-2021:1324RHSA-2021:1322

  • istio Arch Linux 1.10.0-1

arch linux advisories AVG-1947

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-2021-28682 updated cvss 7.5

envoyproxy/envoy: integer overflow handling large grpc-timeouts

  • Red Hat OpenShift Service Mesh 1.1 servicemesh-proxy 1.1.13-1.el8
    fixed: vendor fix RHSA-2021:1322
  • Red Hat OpenShift Service Mesh 2.0 servicemesh-proxy 2.0.3-1.el8
    fixed: vendor fix RHSA-2021:1324
  • Red Hat OpenShift Service Mesh 1.1 servicemesh 1.1.13-3.el8, servicemesh-mixc 1.1.13-3.el8, servicemesh-mixs 1.1.13-3.el8, servicemesh-galley 1.1.13-3.el8, servicemesh-citadel 1.1.13-3.el8, servicemesh-istioctl 1.1.13-3.el8, +3 more
    not affected: vulnerable code not present

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

2.04% chance of exploitation in the next 30 days, higher than 81% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/envoyproxy/envoy/blob/15e3b9dbcc9aaa9d391fa8033904aad1ea1ae70d/api/envoy/api/v2/cluster.proto#L36 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
bitnami envoy
>=1.14.6, <1.14.7
>=1.15.3, <1.15.4
>=1.16.2, <1.16.3
>=1.17.1, <1.17.2
1.14.7
1.15.4
1.16.3
1.17.2

Classification

Weakness
  • CWE-190 Integer Overflow or Wraparound

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.