CVE-2021-32778

mediumpriority · track · 30EPSS 0.012 · 69 %ileEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

1.23% (69th) EPSS

CVSS 5 · medium

Is it mine?

55 products

Check your exposure

Who says so?

5 sources

cnnvd · enisa_euvd · osv · nvd

EPSS · scored 2026-10-27

Envoy is an open source L7 proxy and communication bus designed for large modern service oriented architectures. In affected versions envoy’s procedure for resetting a HTTP/2 stream has O(N^2) complexity, leading to high CPU utilization when a large number of streams are reset. Deployments are susceptible to Denial of Service when Envoy is configured with high limit on H/2 concurrent streams. An attacker wishing to exploit this vulnerability would require a client opening and closing a large number of H/2 streams. Envoy versions 1.19.1, 1.18.4, 1.17.4, 1.16.5 contain fixes to reduce time complexity of resetting HTTP/2 streams. As a workaround users may limit the number of simultaneous HTTP/2 dreams for upstream and downstream peers to a low number, i.e. 100.

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

Fixedservicemesh-0:2.1.0-5.el8.ppc64le as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-0:2.1.0-5.el8.s390x as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-0:2.1.0-5.el8.src as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-0:2.1.0-5.el8.x86_64 as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-cni-0:2.1.0-5.el8.ppc64le as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-cni-0:2.1.0-5.el8.s390x as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-cni-0:2.1.0-5.el8.x86_64 as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-grafana-0:7.2.1-2.el8.ppc64le as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-grafana-0:7.2.1-2.el8.s390x as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-grafana-0:7.2.1-2.el8.src as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-grafana-0:7.2.1-2.el8.x86_64 as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-grafana-debuginfo-0:7.2.1-2.el8.ppc64le as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-grafana-debuginfo-0:7.2.1-2.el8.s390x as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-grafana-debuginfo-0:7.2.1-2.el8.x86_64 as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-operator-0:2.1.0-4.el8.ppc64le as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-operator-0:2.1.0-4.el8.s390x as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-operator-0:2.1.0-4.el8.src as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-operator-0:2.1.0-4.el8.x86_64 as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-pilot-agent-0:2.1.0-5.el8.ppc64le as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-pilot-agent-0:2.1.0-5.el8.s390x as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-pilot-agent-0:2.1.0-5.el8.x86_64 as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-pilot-discovery-0:2.1.0-5.el8.ppc64le as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-pilot-discovery-0:2.1.0-5.el8.s390x as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-pilot-discovery-0:2.1.0-5.el8.x86_64 as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-prometheus-0:2.23.0-1.el8.ppc64le as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-prometheus-0:2.23.0-1.el8.s390x as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-prometheus-0:2.23.0-1.el8.src as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-prometheus-0:2.23.0-1.el8.x86_64 as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-proxy-0:2.1.0-13.el8.ppc64le as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-proxy-0:2.1.0-13.el8.s390x as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-proxy-0:2.1.0-13.el8.src as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-proxy-0:2.1.0-13.el8.x86_64 as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-proxy-debuginfo-0:2.1.0-13.el8.ppc64le as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-proxy-debuginfo-0:2.1.0-13.el8.s390x as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-proxy-debuginfo-0:2.1.0-13.el8.x86_64 as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-proxy-debugsource-0:2.1.0-13.el8.ppc64le as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-proxy-debugsource-0:2.1.0-13.el8.s390x as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-proxy-debugsource-0:2.1.0-13.el8.x86_64 as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-proxy-wasm-0:2.1.0-13.el8.noarch as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-ratelimit-0:2.1.0-1.el8.ppc64le as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-ratelimit-0:2.1.0-1.el8.s390x as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-ratelimit-0:2.1.0-1.el8.src as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051
Fixedservicemesh-ratelimit-0:2.1.0-1.el8.x86_64 as a component of OpenShift Service Mesh 2.1redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHEA-2021:4051

cvss

Technical severity, 0–10. One row per scoring source.

7.5

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 5–7.5

v2.05mediumAV:N/AC:L/Au:N/C:N/I:N/A:Pprimary · NVD / NIST USexploitability 10 · impact 2.9

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 3.6

v3.15.8mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Lsecondary · ENISA EU

v3.15.8mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Lsecondary · security-advisories@github.comexploitability 3.9 · impact 1.4

v3.16.9mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · Red Hat Product Security US

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-834USprimaryCWE-400US

affected products (55)

Products and version ranges known to be affected.

envoyproxy envoy1.16.0, → 1.16.5enisa_euvdEU
envoyproxy envoy1.17.0, → 1.17.4enisa_euvdEU
envoyproxy envoy1.18.0, → 1.18.4enisa_euvdEU
envoyproxy envoy1.19.0, → 1.19.1enisa_euvdEU
envoyproxy envoy1.16.0 → 1.16.5nvdUScpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*
envoyproxy envoy1.17.0 → 1.17.4nvdUScpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*
envoyproxy envoy1.18.0 → 1.18.4nvdUScpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*
envoyproxy envoy= 1.19.0nvdUScpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*
Bitnami envoy1.16.0 → 1.16.5osvUSpkg:bitnami/envoy
Bitnami envoy1.17.0 → 1.17.4osvUSpkg:bitnami/envoy
Bitnami envoy1.18.0 → 1.18.4osvUSpkg:bitnami/envoy
Bitnami envoy1.19.0 → 1.19.1osvUSpkg:bitnami/envoy
servicemesh-0:2.1.0-5.el8.ppc64le as a component of OpenShift Service Mesh 2.1all versionsfixedredhat_csafUS
servicemesh-0:2.1.0-5.el8.s390x as a component of OpenShift Service Mesh 2.1all versionsfixedredhat_csafUS
servicemesh-0:2.1.0-5.el8.src as a component of OpenShift Service Mesh 2.1all versionsfixedredhat_csafUS
servicemesh-0:2.1.0-5.el8.x86_64 as a component of OpenShift Service Mesh 2.1all versionsfixedredhat_csafUS
servicemesh-cni-0:2.1.0-5.el8.ppc64le as a component of OpenShift Service Mesh 2.1all versionsfixedredhat_csafUS
servicemesh-cni-0:2.1.0-5.el8.s390x as a component of OpenShift Service Mesh 2.1all versionsfixedredhat_csafUS
servicemesh-cni-0:2.1.0-5.el8.x86_64 as a component of OpenShift Service Mesh 2.1all versionsfixedredhat_csafUS
servicemesh-grafana-0:7.2.1-2.el8.ppc64le as a component of OpenShift Service Mesh 2.1all versionsfixedredhat_csafUS

showing 20 of 55

advisories (2)

Vendor and ecosystem advisories describing this.

RHEA-2021:4051Red Hat Enhancement Advisory: Red Hat OpenShift Service Mesh 2.1.0 RPMs2021-11-02csaf · redhat_csafUS
Red Hat OpenShift Service Mesh 2.1.0
BIT-envoy-2021-32778Excessive CPU utilization when closing HTTP/2 streams2024-03-06vendor · osvUS
Envoy is an open source L7 proxy and communication bus designed for large modern service oriented architectures. In affected versions envoy’s procedure for resetting a HTTP/2 stream has O(N^2) complexity, leading to high CPU utilization when a large number of streams are reset. Deployments are susceptible to Denial of Service when Envoy is configured with high limit on H/2 concurrent streams. An attacker wishing to exploit this vulnerability would require a client opening and closing a large number of H/2 streams. Envoy versions 1.19.1, 1.18.4, 1.17.4, 1.16.5 contain fixes to reduce time complexity of resetting HTTP/2 streams. As a workaround users may limit the number of simultaneous HTTP/2 dreams for upstream and downstream peers to a low number, i.e. 100.

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd osv nvd redhat_csaf NVD CVE.org MITRE

published 2021-08-24modified 2026-06-17

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+135 more

references (8)

External citations — patches, advisories, analysis.

scry

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