CVE-2023-6563

highpriority · track · 31EPSS 0.012 · 69 %ileDEEUUS

grimoire priorityP2 · Scheduled

Exploitable?

—

no known exploitation

Likely / severe?

1.24% (69th) EPSS

CVSS 7.7 · high

Is it mine?

18 products

Check your exposure

Who says so?

5 sources

cnnvd · enisa_euvd · cert_bund · nvd

EPSS · scored 2026-10-27

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.

cvss

Technical severity, 0–10. One row per scoring source.

7.7

010

base score 0–10 · higher = more severe · hover a vector to decode

v3.17.7highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:Hprimary · NVD / NIST USexploitability 3.1 · impact 4

v3.17.7highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:Hsecondary · ENISA EU

v3.17.7highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:Hsecondary · secalert@redhat.com USexploitability 3.1 · impact 4

v3.17.7highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:Hsecondary · OSV

v3.17.1highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-770USprimaryCWE-770US

affected products (18)

Products and version ranges known to be affected.

Hitachi Ops Centerall versionscert_bundDEcpe:/a:hitachi:ops_center:-
Open Source Keycloakall versionscert_bundDEcpe:/a:keycloak:keycloak:-
Red Hat Enterprise Linuxall versionscert_bundDEcpe:/o:redhat:enterprise_linux:-
Red Hat RHEL-8 based Middleware Containers< 7.6-38enisa_euvdEU
Red Hat RHEL-8 based Middleware Containers< 7.6.6-2enisa_euvdEU
Red Hat Red Hat Single Sign-On 7.6 for RHEL 7< 0:18.0.11-2.redhat_00003.1.el7ssoenisa_euvdEU
Red Hat Red Hat Single Sign-On 7.6 for RHEL 8< 0:18.0.11-2.redhat_00003.1.el8ssoenisa_euvdEU
Red Hat Red Hat Single Sign-On 7.6 for RHEL 9< 0:18.0.11-2.redhat_00003.1.el9ssoenisa_euvdEU
redhat keycloak< 21.0.0nvdUScpe:2.3:a:redhat:keycloak:*:*:*:*:*:*:*:*
redhat openshift container platform= 4.11nvdUScpe:2.3:a:redhat:openshift_container_platform:*:*:*:*:*:*:*:*
redhat openshift container platform= 4.12nvdUScpe:2.3:a:redhat:openshift_container_platform:*:*:*:*:*:*:*:*
redhat openshift container platform for ibm linuxone= 4.10nvdUScpe:2.3:a:redhat:openshift_container_platform_for_ibm_linuxone:*:*:*:*:*:*:*:*
redhat openshift container platform for ibm linuxone= 4.9nvdUScpe:2.3:a:redhat:openshift_container_platform_for_ibm_linuxone:*:*:*:*:*:*:*:*
redhat openshift container platform for power= 4.10nvdUScpe:2.3:a:redhat:openshift_container_platform_for_power:*:*:*:*:*:*:*:*
redhat openshift container platform for power= 4.9nvdUScpe:2.3:a:redhat:openshift_container_platform_for_power:*:*:*:*:*:*:*:*
redhat single sign-onall versionsnvdUScpe:2.3:a:redhat:single_sign-on:*:*:*:*:*:*:*:*
redhat single sign-on= 7.6nvdUScpe:2.3:a:redhat:single_sign-on:*:*:*:*:*:*:*:*
Maven org.keycloak:keycloak-model-jpa< 21.0.0osvUSpkg:maven/org.keycloak/keycloak-model-jpa

advisories (2)

Vendor and ecosystem advisories describing this.

WID-SEC-W-2023-3156Keycloak: Mehrere SchwachstellenDeutsch2023-12-14csaf · cert_bundDE
Ein entfernter, anonymer oder authentisierter Angreifer kann mehrere Schwachstellen in Keycloak ausnutzen, um Sicherheitsvorkehrungen zu umgehen oder einen Denial of Service zu verursachen.
GHSA-54f3-c6hg-865hAllocation of Resources Without Limits in Keycloak2023-12-14ghsa · osvUS
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.

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd cert_bund nvd osv NVD CVE.org MITRE

published 2023-12-14modified 2026-09-22

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+3263 more

references (27)

External citations — patches, advisories, analysis.

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