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Vulnerability details: VCID-khfn-ze7d-5fd5
Vulnerability ID VCID-khfn-ze7d-5fd5
Aliases CVE-2021-3827
GHSA-4pc7-vqv5-5r3v
GMS-2022-1098
Summary ECP SAML binding bypasses authentication flows ### Description A flaw was found in keycloak, where the default ECP binding flow allows other authentication flows to be bypassed. By exploiting this behavior an attacker can bypass the MFA authentication by sending a SOAP request with an AuthnRequest and Authorization header with the user's credentials. The highest threat from this vulnerability is to confidentiality and integrity.
Status Published
Exploitability 0.5
Weighted Severity 8.0
Risk 4.0
Affected and Fixed Packages Package Details
Weaknesses (3)
CWE-287 Improper Authentication
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
System Score Found at
cvssv3 6.8 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-3827.json
cvssv3.1 8.1 https://access.redhat.com/security/cve/CVE-2021-3827
generic_textual HIGH https://access.redhat.com/security/cve/CVE-2021-3827
epss 0.00092 https://api.first.org/data/v1/epss?cve=CVE-2021-3827
epss 0.00092 https://api.first.org/data/v1/epss?cve=CVE-2021-3827
epss 0.00092 https://api.first.org/data/v1/epss?cve=CVE-2021-3827
epss 0.00092 https://api.first.org/data/v1/epss?cve=CVE-2021-3827
epss 0.00092 https://api.first.org/data/v1/epss?cve=CVE-2021-3827
epss 0.00092 https://api.first.org/data/v1/epss?cve=CVE-2021-3827
epss 0.00092 https://api.first.org/data/v1/epss?cve=CVE-2021-3827
epss 0.00092 https://api.first.org/data/v1/epss?cve=CVE-2021-3827
epss 0.00092 https://api.first.org/data/v1/epss?cve=CVE-2021-3827
epss 0.00092 https://api.first.org/data/v1/epss?cve=CVE-2021-3827
epss 0.00092 https://api.first.org/data/v1/epss?cve=CVE-2021-3827
epss 0.00092 https://api.first.org/data/v1/epss?cve=CVE-2021-3827
epss 0.00092 https://api.first.org/data/v1/epss?cve=CVE-2021-3827
epss 0.00092 https://api.first.org/data/v1/epss?cve=CVE-2021-3827
epss 0.00092 https://api.first.org/data/v1/epss?cve=CVE-2021-3827
epss 0.00092 https://api.first.org/data/v1/epss?cve=CVE-2021-3827
epss 0.00092 https://api.first.org/data/v1/epss?cve=CVE-2021-3827
epss 0.00092 https://api.first.org/data/v1/epss?cve=CVE-2021-3827
epss 0.00092 https://api.first.org/data/v1/epss?cve=CVE-2021-3827
cvssv3.1 8.1 https://bugzilla.redhat.com/show_bug.cgi?id=2007512
generic_textual HIGH https://bugzilla.redhat.com/show_bug.cgi?id=2007512
cvssv3.1_qr HIGH https://github.com/advisories/GHSA-4pc7-vqv5-5r3v
cvssv3.1 8.1 https://github.com/keycloak/keycloak
generic_textual HIGH https://github.com/keycloak/keycloak
cvssv3.1 8.1 https://github.com/keycloak/keycloak/commit/44000caaf5051d7f218d1ad79573bd3d175cad0d
generic_textual HIGH https://github.com/keycloak/keycloak/commit/44000caaf5051d7f218d1ad79573bd3d175cad0d
cvssv3.1 8.1 https://github.com/keycloak/keycloak/security/advisories/GHSA-4pc7-vqv5-5r3v
cvssv3.1_qr HIGH https://github.com/keycloak/keycloak/security/advisories/GHSA-4pc7-vqv5-5r3v
generic_textual HIGH https://github.com/keycloak/keycloak/security/advisories/GHSA-4pc7-vqv5-5r3v
cvssv3.1 6.8 https://nvd.nist.gov/vuln/detail/CVE-2021-3827
cvssv3.1 8.1 https://nvd.nist.gov/vuln/detail/CVE-2021-3827
generic_textual HIGH https://nvd.nist.gov/vuln/detail/CVE-2021-3827
archlinux High https://security.archlinux.org/AVG-1332
Reference id Reference type URL
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-3827.json
https://access.redhat.com/security/cve/CVE-2021-3827
https://api.first.org/data/v1/epss?cve=CVE-2021-3827
https://bugzilla.redhat.com/show_bug.cgi?id=2007512
https://github.com/keycloak/keycloak
https://github.com/keycloak/keycloak/commit/44000caaf5051d7f218d1ad79573bd3d175cad0d
https://github.com/keycloak/keycloak/security/advisories/GHSA-4pc7-vqv5-5r3v
https://nvd.nist.gov/vuln/detail/CVE-2021-3827
AVG-1332 https://security.archlinux.org/AVG-1332
cpe:2.3:a:redhat:keycloak:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:redhat:keycloak:*:*:*:*:*:*:*:*
cpe:2.3:a:redhat:single_sign-on:7.0:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:redhat:single_sign-on:7.0:*:*:*:*:*:*:*
GHSA-4pc7-vqv5-5r3v https://github.com/advisories/GHSA-4pc7-vqv5-5r3v
RHSA-2022:0151 https://access.redhat.com/errata/RHSA-2022:0151
RHSA-2022:0152 https://access.redhat.com/errata/RHSA-2022:0152
RHSA-2022:0155 https://access.redhat.com/errata/RHSA-2022:0155
RHSA-2022:0164 https://access.redhat.com/errata/RHSA-2022:0164
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-3827.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:L/UI:N/S:U/C:H/I:H/A:N Found at https://access.redhat.com/security/cve/CVE-2021-3827
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:L/UI:N/S:U/C:H/I:H/A:N Found at https://bugzilla.redhat.com/show_bug.cgi?id=2007512
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:L/UI:N/S:U/C:H/I:H/A:N Found at https://github.com/keycloak/keycloak
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:L/UI:N/S:U/C:H/I:H/A:N Found at https://github.com/keycloak/keycloak/commit/44000caaf5051d7f218d1ad79573bd3d175cad0d
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:L/UI:N/S:U/C:H/I:H/A:N Found at https://github.com/keycloak/keycloak/security/advisories/GHSA-4pc7-vqv5-5r3v
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:H/PR:L/UI:N/S:U/C:H/I:H/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2021-3827
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:L/UI:N/S:U/C:H/I:H/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2021-3827
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 0.27039
EPSS Score 0.00092
Published At July 30, 2025, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2025-07-31T08:59:27.178087+00:00 GithubOSV Importer Import https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2022/04/GHSA-4pc7-vqv5-5r3v/GHSA-4pc7-vqv5-5r3v.json 37.0.0