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Vulnerability details: VCID-dr72-63u4-aaaj
Vulnerability ID VCID-dr72-63u4-aaaj
Aliases CVE-2021-32777
Summary 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.
Status Published
Exploitability 0.5
Weighted Severity 8.0
Risk 4.0
Affected and Fixed Packages Package Details
Weaknesses (1)
CWE-863 Incorrect Authorization
System Score Found at
rhas Important https://access.redhat.com/errata/RHSA-2021:3272
rhas Important https://access.redhat.com/errata/RHSA-2021:3273
cvssv3 8.3 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-32777.json
epss 0.00014 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
epss 0.00104 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
epss 0.00104 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
epss 0.00104 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
epss 0.00104 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
epss 0.00104 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
epss 0.00104 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
epss 0.00104 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
epss 0.00104 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
epss 0.00104 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
epss 0.00104 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
epss 0.00104 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
epss 0.00105 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
epss 0.00105 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
epss 0.00105 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
epss 0.00105 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
epss 5e-05 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
epss 5e-05 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
epss 5e-05 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
epss 5e-05 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
epss 5e-05 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
epss 5e-05 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
epss 5e-05 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
epss 5e-05 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
epss 5e-05 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
epss 5e-05 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
epss 5e-05 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
epss 5e-05 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
epss 5e-05 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
epss 5e-05 https://api.first.org/data/v1/epss?cve=CVE-2021-32777
rhbs high https://bugzilla.redhat.com/show_bug.cgi?id=1996933
cvssv3.1 8.6 https://github.com/envoyproxy/envoy/security/advisories/GHSA-6g4j-5vrw-2m8h
generic_textual HIGH https://github.com/envoyproxy/envoy/security/advisories/GHSA-6g4j-5vrw-2m8h
cvssv2 7.5 https://nvd.nist.gov/vuln/detail/CVE-2021-32777
cvssv3 8.3 https://nvd.nist.gov/vuln/detail/CVE-2021-32777
cvssv3.1 8.3 https://nvd.nist.gov/vuln/detail/CVE-2021-32777
archlinux High https://security.archlinux.org/AVG-2321
Reference id Reference type URL
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-32777.json
https://api.first.org/data/v1/epss?cve=CVE-2021-32777
https://github.com/envoyproxy/envoy/security/advisories/GHSA-6g4j-5vrw-2m8h
https://www.envoyproxy.io/docs/envoy/v1.19.0/version_history/version_history
1996933 https://bugzilla.redhat.com/show_bug.cgi?id=1996933
AVG-2321 https://security.archlinux.org/AVG-2321
cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*
cpe:2.3:a:envoyproxy:envoy:1.19.0:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:envoyproxy:envoy:1.19.0:*:*:*:*:*:*:*
CVE-2021-32777 https://nvd.nist.gov/vuln/detail/CVE-2021-32777
ISTIO-SECURITY-2021-008 https://istio.io/latest/news/security/ISTIO-SECURITY-2021-008/
RHSA-2021:3272 https://access.redhat.com/errata/RHSA-2021:3272
RHSA-2021:3273 https://access.redhat.com/errata/RHSA-2021:3273
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-32777.json
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N Found at https://github.com/envoyproxy/envoy/security/advisories/GHSA-6g4j-5vrw-2m8h
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: AV:N/AC:L/Au:N/C:P/I:P/A:P Found at https://nvd.nist.gov/vuln/detail/CVE-2021-32777
Exploitability (E) Access Vector (AV) Access Complexity (AC) Authentication (Au) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

high

functional

unproven

proof_of_concept

not_defined

local

adjacent_network

network

high

medium

low

multiple

single

none

none

partial

complete

none

partial

complete

none

partial

complete
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L Found at https://nvd.nist.gov/vuln/detail/CVE-2021-32777
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L Found at https://nvd.nist.gov/vuln/detail/CVE-2021-32777
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Exploit Prediction Scoring System (EPSS)
Percentile 0.00905
EPSS Score 0.00014
Published At March 29, 2025, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
There are no relevant records.