CVE-2023-0264

Keycloak vulnerable to user impersonation via stolen UUID code

5.0 MediumPublic exploitFix available

A flaw was found in Keycloaks OpenID Connect user authentication, which may incorrectly authenticate requests. An authenticated attacker who could obtain information from a user request within the same realm could use that data to impersonate the victim and generate new session tokens. This issue could impact confidentiality, integrity, and availability.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: High
Privileges needed: Low
User interaction: None

What an attacker can affect

Confidentiality: Low
Integrity: Low
Availability: Low

Exploit likelihood

1.27%Up 1.2 points since Aug 5, 2023

What each source reports

NVD Score used 5.0

Record: CVE-2023-0264
CVSS 3.1: 5.0 MediumCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L
Weakness: CWE-287
Updated: 2026-11-02

CVE List No score

Record: CVE-2023-0264
Updated: 2026-11-02

EUVDEUVD-2023-0967 0.0

Record: EUVD-2023-0967
CVSS: 0.0 NoneCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L
Updated: 2026-11-03

GitHub AdvisoriesGHSA-9g98-5mj6-f9mv 8.7

Keycloak vulnerable to user impersonation via stolen UUID code

Keycloak's OpenID Connect user authentication was found to incorrectly authenticate requests. An authenticated attacker who could also obtain a certain piece of info from a user request, from a victim within the same realm, could use that data to impersonate the victim and generate new session tokens.

Record: GHSA-9g98-5mj6-f9mv
CVSS 3.1: 8.7 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
Weakness: CWE-287, CWE-345
Updated: 2026-11-02

OSVGHSA-9g98-5mj6-f9mv 8.7

Keycloak vulnerable to user impersonation via stolen UUID code

Record: GHSA-9g98-5mj6-f9mv
CVSS 3.1: 8.7 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
Weakness: CWE-287, CWE-345
Updated: 2026-11-02

OSVRHSA-2023:1043 9.8

Red Hat Security Advisory: Red Hat Single Sign-On 7.6.2 security update on RHEL 7

Record: RHSA-2023:1043
CVSS 3.1: 9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated: 2026-11-02

OSVRHSA-2023:1044 9.8

Red Hat Security Advisory: Red Hat Single Sign-On 7.6.2 security update on RHEL 8

Record: RHSA-2023:1044
CVSS 3.1: 9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated: 2026-11-02

OSVRHSA-2023:1045 9.8

Red Hat Security Advisory: Red Hat Single Sign-On 7.6.2 security update on RHEL 9

Record: RHSA-2023:1045
CVSS 3.1: 9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`org.keycloak:keycloak-services` Maven	before 21.0.1	21.0.1
`org.keycloak:keycloak-services` Maven	before 21.0.1, plus listed versions 1.0-alpha-11.0-alpha-1-120620131.0-alpha-21.0-alpha-31.0-alpha-4 Show 45 moreShow less 1.0-beta-11.0-beta-1-201505211.0-beta-1-201505231.0-beta-21.0-beta-31.0-beta-41.0-final1.0-rc-11.0-rc-21.0.1.Final1.0.2.Final1.0.3.Final1.0.4.Final1.0.5.Final1.1.0.Beta11.1.0.Beta21.1.0.Final1.1.1.Final1.2.0.Beta11.2.0.CR11.2.0.Final1.3.0.Final1.3.1.Final1.4.0.Final1.5.0-Final1.5.0.Final1.5.1.Final1.6.0.Final1.6.1.Final1.7.0.CR11.7.0.Final1.8.0.Alpha11.8.0.CR11.8.0.CR21.8.0.CR31.8.0.Final1.8.1.Final1.9.0.CR11.9.0.Final1.9.1.Final1.9.2.Final1.9.3.Final1.9.4.Final1.9.5.Final1.9.7.Final	21.0.1
`rh-sso7-keycloak` Red Hat:red_hat_single_sign_on:7.6::el7	before 0:18.0.6-1.redhat_00001.1.el7sso	0:18.0.6-1.redhat_00001.1.el7sso
`rh-sso7-keycloak-server` Red Hat:red_hat_single_sign_on:7.6::el7	before 0:18.0.6-1.redhat_00001.1.el7sso	0:18.0.6-1.redhat_00001.1.el7sso
`rh-sso7-keycloak` Red Hat:red_hat_single_sign_on:7.6::el8	before 0:18.0.6-1.redhat_00001.1.el8sso	0:18.0.6-1.redhat_00001.1.el8sso
`rh-sso7-keycloak-server` Red Hat:red_hat_single_sign_on:7.6::el8	before 0:18.0.6-1.redhat_00001.1.el8sso	0:18.0.6-1.redhat_00001.1.el8sso
`rh-sso7-keycloak` Red Hat:red_hat_single_sign_on:7.6::el9	before 0:18.0.6-1.redhat_00001.1.el9sso	0:18.0.6-1.redhat_00001.1.el9sso
`rh-sso7-keycloak-server` Red Hat:red_hat_single_sign_on:7.6::el9	before 0:18.0.6-1.redhat_00001.1.el9sso	0:18.0.6-1.redhat_00001.1.el9sso

Public exploits

Links only. Every CVE stores no exploit code.

Public exploits
Source	Link	Date
PoC in GitHub	ElianGonzi00/pocKeycloakCVE-2023-0264	2026-07-28
PoC in GitHub	twwd/CVE-2023-0264	2023-03-06

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases, products	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV, PoC in GitHub

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2023-0264 is a medium vulnerability (CVSS 5.0) in Keycloak, published March 2, 2023. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 1.27%, the 70th percentile. Fixed in org.keycloak:keycloak-services 21.0.1.

References

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