CVE-2023-2422 | Keycloak: oauth client impersonation

A flaw was found in Keycloak. A Keycloak server configured to support mTLS authentication for OAuth/OpenID clients does not properly verify the client certificate chain. A client that possesses a proper certificate can authorize itself as any other client, therefore, access data that belongs to other clients.

Published: 2023-10-04 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-2422 is rated Low Risk (34.1/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.43%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2023-2422

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.29% 0.43% +0.14%
2 2025-11-21 0.21% 0.29% +0.08%
3 2025-11-18 — 0.21% —

Full EPSS history (9 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-2422

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:H)
They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 1.2 4.2 [email protected]
7.1 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 4.2 [email protected]

Weakness enumeration for CVE-2023-2422

GitHub Security Advisory for CVE-2023-2422

GHSA-3qh5-qqj2-c78f · Severity: high · Ecosystem: maven — Keycloak vulnerable to Improper Client Certificate Validation for OAuth/OpenID clients

OS Trackers for CVE-2023-2422

vendor priority summary link
redhat medium — https://access.redhat.com/security/cve/CVE-2023-2422

Affected software / configurations for CVE-2023-2422

Vendor Product Version Raw CPE
redhat keycloak — cpe:2.3:a:redhat:keycloak:-:*:*:*:*:*:*:*
redhat openshift_container_platform 4.9 cpe:2.3:a:redhat:openshift_container_platform:4.9:*:*:*:*:*:*:*
redhat openshift_container_platform 4.10 cpe:2.3:a:redhat:openshift_container_platform:4.10:*:*:*:*:*:*:*
redhat openshift_container_platform 4.11 cpe:2.3:a:redhat:openshift_container_platform:4.11:*:*:*:*:*:*:*
redhat openshift_container_platform 4.12 cpe:2.3:a:redhat:openshift_container_platform:4.12:*:*:*:*:*:*:*
redhat single_sign-on 7.6 cpe:2.3:a:redhat:single_sign-on:7.6:*:*:*:*:*:*:*

References for CVE-2023-2422

cvelogic Threat Intelligence