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☕ Maven
Not in CISA KEV
HIGH severity

CVE-2023-6563 — keycloak-model-jpa

HIGHFix: keycloak/keycloak#15463

CVE-2023-6563 is a high-severity (CVSS 7.7) CWE-770 vulnerability in org.keycloak:keycloak-model-jpa. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for org.keycloak:keycloak-model-jpa — see the affected versions and patch details below.

Keycloak: offline session token dos

Also known asGHSA-54f3-c6hg-865h
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
1 known
Exploitation data as of Nov 3, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.2%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs69th percentile — riskier than 69% of all scored CVEsHighest risk
0.04%0.61%1.17%1.74%0.5%1.2%May 26Sep 26Nov 26

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-model-jpa

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

An unconstrained memory consumption vulnerability was discovered in Keycloak. It can be triggered in environments which have millions of offline tokens (> 500,000 users with each having at least 2 saved sessions). If an attacker creates two or more user sessions and then open the "consents" tab of the admin User Interface, the UI attempts to load a huge number of offline client sessions leading to excessive memory and CPU consumption which could potentially crash the entire system.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
☕Mavenorg.keycloak:keycloak-model-jpaall versions21.0.0org.keycloak:keycloak-model-jpa:21.0.0

Affected Products

5 products · 9 configurations
Application
keycloakredhat
< 21.0.0
range
Application
openshift container platformredhat
2 versions
4.114.12
Application
openshift container platform for ibm linuxoneredhat
2 versions
4.94.10
Application
openshift container platform for powerredhat
2 versions
4.94.10
Application
single sign-onredhat
1 version
7.6
Exploits & PoCs
1

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

An unconstrained memory consumption vulnerability was discovered in Keyc…

access.redhat.comNVDDec 2023

Detection & mitigation playbook

Open-source dependency

  1. Detect

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

  2. Fix

    Update org.keycloak:keycloak-model-jpa to 21.0.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-6563 is resolved across your whole dependency graph.

  3. Workarounds

    Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

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 HatImportant

While this vulnerability can enable complete compromise of system availability, it is not possible to be triggered in every environment. The impact is rated as Important due to several preconditions (number of users and how many sessions each user has) which are beyond an attacker's control.

Workaround published by Red Hat
There are three main options to prevent exploitation: 1) If you are using a reverse proxy, block the consents URL. 2) This option is less effective: remove the consents application tab from the account console theme. 3) This option has a significant negative impact on end users: entirely disable offline user profiles.
Source: Red Hat security advisory for CVE-2023-6563 (CC BY 4.0)
ProductFixed inAdvisory
Red Hat Single Sign-On 7.6 for RHEL 7rh-sso7-keycloak-0:18.0.11-2.redhat_00003.1.el7ssoRHSA-2023:7854
Red Hat Single Sign-On 7.6 for RHEL 8rh-sso7-keycloak-0:18.0.11-2.redhat_00003.1.el8ssoRHSA-2023:7856
Red Hat Single Sign-On 7.6 for RHEL 9rh-sso7-keycloak-0:18.0.11-2.redhat_00003.1.el9ssoRHSA-2023:7855
RHEL-8 based Middleware Containersrh-sso-7/sso76-openshift-rhel8:7.6-38RHSA-2023:7857
Single Sign-On 7.6.6rh-sso7-keycloakRHSA-2023:7858

Frequently Asked Questions

An unconstrained memory consumption vulnerability was discovered in Keycloak. It can be triggered in environments which have millions of offline tokens (> 500,000 users with each having at least 2 saved sessions). If an attacker creates two or more user sessions and then open the "consents" tab of the admin User Interface, the UI attempts to load a huge number of offline client sessions leading to excessive memory and CPU consumption which could potentially crash the entire system.
O3 Security · Impact-Aware SCA

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CVE-2023-6563: keycloak-model-jpa — Fixed in 21.0.0