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Vulnerability details: VCID-nhey-k3qb-rubf
Vulnerability ID VCID-nhey-k3qb-rubf
Aliases CVE-2021-3424
GHSA-pf38-cw3p-22q9
Summary Keycloak is vulnerable to IDN homograph attack A flaw was found in keycloak as shipped in Red Hat Single Sign-On 7.4 where IDN homograph attacks are possible. A malicious user can register himself with a name already registered and trick admin to grant him extra privileges.
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 5.3 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-3424.json
epss 0.00164 https://api.first.org/data/v1/epss?cve=CVE-2021-3424
epss 0.00164 https://api.first.org/data/v1/epss?cve=CVE-2021-3424
epss 0.00164 https://api.first.org/data/v1/epss?cve=CVE-2021-3424
epss 0.00164 https://api.first.org/data/v1/epss?cve=CVE-2021-3424
epss 0.00164 https://api.first.org/data/v1/epss?cve=CVE-2021-3424
epss 0.00164 https://api.first.org/data/v1/epss?cve=CVE-2021-3424
epss 0.00164 https://api.first.org/data/v1/epss?cve=CVE-2021-3424
epss 0.00164 https://api.first.org/data/v1/epss?cve=CVE-2021-3424
epss 0.00164 https://api.first.org/data/v1/epss?cve=CVE-2021-3424
epss 0.00164 https://api.first.org/data/v1/epss?cve=CVE-2021-3424
epss 0.00164 https://api.first.org/data/v1/epss?cve=CVE-2021-3424
epss 0.00164 https://api.first.org/data/v1/epss?cve=CVE-2021-3424
epss 0.00164 https://api.first.org/data/v1/epss?cve=CVE-2021-3424
epss 0.00164 https://api.first.org/data/v1/epss?cve=CVE-2021-3424
epss 0.00164 https://api.first.org/data/v1/epss?cve=CVE-2021-3424
epss 0.00164 https://api.first.org/data/v1/epss?cve=CVE-2021-3424
epss 0.00164 https://api.first.org/data/v1/epss?cve=CVE-2021-3424
cvssv3.1 5.3 https://bugzilla.redhat.com/show_bug.cgi?id=1933320
generic_textual MODERATE https://bugzilla.redhat.com/show_bug.cgi?id=1933320
cvssv3.1_qr MODERATE https://github.com/advisories/GHSA-pf38-cw3p-22q9
cvssv3.1 5.3 https://github.com/keycloak/keycloak
generic_textual MODERATE https://github.com/keycloak/keycloak
cvssv2 5.0 https://nvd.nist.gov/vuln/detail/CVE-2021-3424
cvssv3.1 5.3 https://nvd.nist.gov/vuln/detail/CVE-2021-3424
generic_textual MODERATE https://nvd.nist.gov/vuln/detail/CVE-2021-3424
archlinux High https://security.archlinux.org/AVG-1332
Reference id Reference type URL
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-3424.json
https://api.first.org/data/v1/epss?cve=CVE-2021-3424
https://bugzilla.redhat.com/show_bug.cgi?id=1933320
https://github.com/keycloak/keycloak
https://nvd.nist.gov/vuln/detail/CVE-2021-3424
AVG-1332 https://security.archlinux.org/AVG-1332
cpe:2.3:a:redhat:single_sign-on:7.4:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:redhat:single_sign-on:7.4:*:*:*:*:*:*:*
GHSA-pf38-cw3p-22q9 https://github.com/advisories/GHSA-pf38-cw3p-22q9
RHSA-2021:2063 https://access.redhat.com/errata/RHSA-2021:2063
RHSA-2021:2064 https://access.redhat.com/errata/RHSA-2021:2064
RHSA-2021:2065 https://access.redhat.com/errata/RHSA-2021:2065
RHSA-2021:2070 https://access.redhat.com/errata/RHSA-2021:2070
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-3424.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:U/C:N/I:L/A:N Found at https://bugzilla.redhat.com/show_bug.cgi?id=1933320
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:U/C:N/I:L/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: AV:N/AC:L/Au:N/C:N/I:P/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2021-3424
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:U/C:N/I:L/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2021-3424
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 0.3801
EPSS Score 0.00164
Published At July 30, 2025, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2025-07-31T08:59:31.391469+00:00 GithubOSV Importer Import https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2022/04/GHSA-pf38-cw3p-22q9/GHSA-pf38-cw3p-22q9.json 37.0.0