How severe is CVE-2023-0091?

CVE-2023-0091 has a CVSS score of 6.5/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2023-0091?

CVE-2023-0091 affects the following packages: org.keycloak:keycloak-core (Maven). Ecosystems affected: Maven.

How do I fix CVE-2023-0091?

Update org.keycloak:keycloak-core to 20.0.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-0091 is resolved across your whole dependency graph.

How do I detect CVE-2023-0091 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.keycloak:keycloak-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2023-0091 if there is no patch (or I can't update yet)?

Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Is CVE-2023-0091 actively exploited in the wild?

No public exploit code has been indexed for CVE-2023-0091 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2023-0091?

CVE-2023-0091 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 42th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2023-0091?

CVE-2023-0091 is classified as CWE-863 (CWE-863). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2023-0091 published, and has it been updated?

CVE-2023-0091 was published on January 12, 2023 and was last updated on November 8, 2023. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

Not in CISA KEV

MEDIUM severity

CVE-2023-0091 — keycloak-core

MEDIUM

CVE-2023-0091 is a medium-severity (CVSS 6.5) CWE-863 vulnerability in org.keycloak:keycloak-core. A fix is available for org.keycloak:keycloak-core — see the affected versions and patch details below.

Keycloak has lack of validation of access token on client registrations endpoint

Published

Jan 12, 2023

Updated

Nov 8, 2023

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 5, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2023-0091.

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs42th percentile — riskier than 42% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

☕org.keycloak:keycloak-core

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

When a service account with the create-client or manage-clients role can use the client-registration endpoints to create/manage clients with an access token.

If the access token is leaked, there is an option to revoke the specific token. However, the check is not performed in client-registration endpoints.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.keycloak:keycloak-core`	all versions	20.0.3`org.keycloak:keycloak-core:20.0.3`

Affected Products

1 product · 1 configurations

Application

keycloakredhat

all

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.keycloak:keycloak-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.keycloak:keycloak-core to 20.0.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-0091 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatLow

Product	Fixed in	Advisory
Red Hat Single Sign-On 7	`rh-sso7-keycloak`	RHSA-2023:1049
Red Hat Single Sign-On 7.6 for RHEL 7	`rh-sso7-keycloak-0:18.0.6-1.redhat_00001.1.el7sso`	RHSA-2023:1043
Red Hat Single Sign-On 7.6 for RHEL 8	`rh-sso7-keycloak-0:18.0.6-1.redhat_00001.1.el8sso`	RHSA-2023:1044
Red Hat Single Sign-On 7.6 for RHEL 9	`rh-sso7-keycloak-0:18.0.6-1.redhat_00001.1.el9sso`	RHSA-2023:1045
RHEL-8 based Middleware Containers	`rh-sso-7/sso76-openshift-rhel8:7.6-20`	RHSA-2023:1047

Frequently Asked Questions

When a service account with the create-client or manage-clients role can use the client-registration endpoints to create/manage clients with an access token. If the access token is leaked, there is an option to revoke the specific token. However, the check is not performed in client-registration endpoints.

O3 Security · Impact-Aware SCA

Is CVE-2023-0091 in your dependencies?

Find it across Maven, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

6.5/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

Low

Availability

None

Raw vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

CWE Classification

CWE-863CWE-863

Weaponization

No Nuclei template, Metasploit module or public proof-of-concept found.

OpenSSF Scorecard

Package health score

keycloak

9.3/10

Code-Review10/10

Maintained10/10

Branch-Protection8/10

Assessed Nov 2, 2026

Timeline

Disclosed

Jan 12, 2023

Last updated

Nov 8, 2023

Identifiers

CVE-2023-0091

References

Advisorynvd.nist.gov · CVE 2023 0091 Webgithub.com · GHSA v436 q368 hvgg Webaccess.redhat.com · CVE 2023 0091 Packagegithub.com · keycloak

Related vulnerabilities

This CVE is medium severity; 7 of 8 other CVEs affecting keycloak-core are rated as high or higher (top: high).

CVE-2024-4028CVE-2024-10039CVE-2024-7318CVE-2023-6841CVE-2024-7260CVE-2023-6927CVE-2023-4918CVE-2023-0105

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedNov 8, 2023

CVE-2023-0091 — keycloak-core

Exploitation Status

No confirmed exploitation observed yet

EPSS Exploitation Probability

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

Description

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

Fixing This On Your OS

Frequently Asked Questions

Is CVE-2023-0091 in your dependencies?