CVE-2021-32777

highpriority · track · 34OT risk · elevatedEPSS 0.033 · 89 %ileEUUS

grimoire priorityP2 · Scheduled

Exploitable?

—

no known exploitation

Likely / severe?

3.33% (89th) EPSS

CVSS 7.5 · high

Is it mine?

67 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 when ext-authz extension is sending request headers to the external authorization service it must merge multiple value headers according to the HTTP spec. However, only the last header value is sent. This may allow specifically crafted requests to bypass authorization. Attackers may be able to escalate privileges when using ext-authz extension or back end service that uses multiple value headers for authorization. A specifically constructed request may be delivered by an untrusted downstream peer in the presence of ext-authz extension. Envoy versions 1.19.1, 1.18.4, 1.17.4, 1.16.5 contain fixes to the ext-authz extension to correctly merge multiple request header values, when sending request for authorization.

remediations

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

A vendor fix is available.

Fixedservicemesh-proxy-0:2.0.7-3.el8.ppc64le as a component of OpenShift Service Mesh 2.0redhat_csaf
The OpenShift Service Mesh Release Notes provide information on the features and known issues: https://docs.openshift.com/container-platform/latest/service_mesh/v2x/servicemesh-release-notes.html
https://access.redhat.com/errata/RHSA-2021:3272
Fixedservicemesh-proxy-0:2.0.7-3.el8.s390x as a component of OpenShift Service Mesh 2.0redhat_csaf
The OpenShift Service Mesh Release Notes provide information on the features and known issues: https://docs.openshift.com/container-platform/latest/service_mesh/v2x/servicemesh-release-notes.html
https://access.redhat.com/errata/RHSA-2021:3272
Fixedservicemesh-proxy-0:2.0.7-3.el8.src as a component of OpenShift Service Mesh 2.0redhat_csaf
The OpenShift Service Mesh Release Notes provide information on the features and known issues: https://docs.openshift.com/container-platform/latest/service_mesh/v2x/servicemesh-release-notes.html
https://access.redhat.com/errata/RHSA-2021:3272
Fixedservicemesh-proxy-0:2.0.7-3.el8.x86_64 as a component of OpenShift Service Mesh 2.0redhat_csaf
The OpenShift Service Mesh Release Notes provide information on the features and known issues: https://docs.openshift.com/container-platform/latest/service_mesh/v2x/servicemesh-release-notes.html
https://access.redhat.com/errata/RHSA-2021:3272
Fixedservicemesh-proxy-0:1.1.17-2.el8.ppc64le as a component of OpenShift Service Mesh 1.1redhat_csaf
The OpenShift Service Mesh Release Notes provide information on the features and known issues: https://docs.openshift.com/container-platform/4.8/service_mesh/v1x/servicemesh-release-notes.html
https://access.redhat.com/errata/RHSA-2021:3273
Fixedservicemesh-proxy-0:1.1.17-2.el8.s390x as a component of OpenShift Service Mesh 1.1redhat_csaf
The OpenShift Service Mesh Release Notes provide information on the features and known issues: https://docs.openshift.com/container-platform/4.8/service_mesh/v1x/servicemesh-release-notes.html
https://access.redhat.com/errata/RHSA-2021:3273
Fixedservicemesh-proxy-0:1.1.17-2.el8.src as a component of OpenShift Service Mesh 1.1redhat_csaf
The OpenShift Service Mesh Release Notes provide information on the features and known issues: https://docs.openshift.com/container-platform/4.8/service_mesh/v1x/servicemesh-release-notes.html
https://access.redhat.com/errata/RHSA-2021:3273
Fixedservicemesh-proxy-0:1.1.17-2.el8.x86_64 as a component of OpenShift Service Mesh 1.1redhat_csaf
The OpenShift Service Mesh Release Notes provide information on the features and known issues: https://docs.openshift.com/container-platform/4.8/service_mesh/v1x/servicemesh-release-notes.html
https://access.redhat.com/errata/RHSA-2021:3273

cvss

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

8.6

010

base score 0–10 · higher = more severe · hover a vector to decode

v2.07.5highAV:N/AC:L/Au:N/C:P/I:P/A:Pprimary · NVD / NIST USexploitability 10 · impact 6.4

v3.18.3highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:Lprimary · NVD / NIST USexploitability 3.9 · impact 3.7

v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:Nsecondary · ENISA EU

v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:Nsecondary · security-advisories@github.comexploitability 3.9 · impact 4

v3.17.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L/E:Usecondary · CVSS-BT (t0sche)

v3.18.3highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:Lsecondary · Red Hat Product Security US

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-863USprimaryCWE-551USCWE-863US

affected products (67)

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-0:1.1.17-3.el8.ppc64le as a component of OpenShift Service Mesh 1.1all versionsnot affectedredhat_csafUS
servicemesh-0:1.1.17-3.el8.s390x as a component of OpenShift Service Mesh 1.1all versionsnot affectedredhat_csafUS
servicemesh-0:1.1.17-3.el8.src as a component of OpenShift Service Mesh 1.1all versionsnot affectedredhat_csafUS
servicemesh-0:1.1.17-3.el8.x86_64 as a component of OpenShift Service Mesh 1.1all versionsnot affectedredhat_csafUS
servicemesh-0:2.0.7-3.el8.ppc64le as a component of OpenShift Service Mesh 2.0all versionsnot affectedredhat_csafUS
servicemesh-0:2.0.7-3.el8.s390x as a component of OpenShift Service Mesh 2.0all versionsnot affectedredhat_csafUS
servicemesh-0:2.0.7-3.el8.src as a component of OpenShift Service Mesh 2.0all versionsnot affectedredhat_csafUS
servicemesh-0:2.0.7-3.el8.x86_64 as a component of OpenShift Service Mesh 2.0all versionsnot affectedredhat_csafUS

showing 20 of 67

advisories (3)

Vendor and ecosystem advisories describing this.

RHSA-2021:3272Red Hat Security Advisory: Red Hat OpenShift Service Mesh 2.0.7.1 security update2021-08-25csaf · redhat_csafUS
An update for servicemesh and servicemesh-proxy is now available for OpenShift Service Mesh 2.0. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.
RHSA-2021:3273Red Hat Security Advisory: Red Hat OpenShift Service Mesh 1.1.17.1 security update2021-08-25csaf · redhat_csafUS
An update for servicemesh and servicemesh-proxy is now available for OpenShift Service Mesh 1.1. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.
BIT-envoy-2021-32777Incorrect concatenation of multiple value request headers in ext-authz extension2024-03-06vendor · osvUS
Envoy is an open source L7 proxy and communication bus designed for large modern service oriented architectures. In affected versions when ext-authz extension is sending request headers to the external authorization service it must merge multiple value headers according to the HTTP spec. However, only the last header value is sent. This may allow specifically crafted requests to bypass authorization. Attackers may be able to escalate privileges when using ext-authz extension or back end service that uses multiple value headers for authorization. A specifically constructed request may be delivered by an untrusted downstream peer in the presence of ext-authz extension. Envoy versions 1.19.1, 1.18.4, 1.17.4, 1.16.5 contain fixes to the ext-authz extension to correctly merge multiple request header values, when sending request for authorization.

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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+5004 more

references (9)

External citations — patches, advisories, analysis.

scry

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