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Vulnerabilities

Vulnerability · CVE-2023-6563

An unconstrained memory consumption vulnerability was discovered in Keycloak.

Published Dec 14, 2023 · catalog updated Sep 22, 2026 · An unconstrained memory consumption

Last checked Nov 6, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2023-6563. EPSS is 1.24%. Act only if a listed version of An unconstrained memory consumption is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (An unconstrained memory consumption).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
High7.7
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
1.24%
Remediation
Version ranges on file
Affected products
cpe redhat/keycloak · cpe redhat/openshift container platform · cpe redhat/openshift container platform for power · cpe redhat/single sign-on

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe redhat/keycloak< 21.0.0
  • cpe redhat/openshift container platform4.11
  • cpe redhat/openshift container platform4.12
  • cpe redhat/openshift container platform for power4.10
  • cpe redhat/openshift container platform for power4.9
  • cpe redhat/single sign-on7.6

How to fix CVE-2023-6563

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2023-6563. EPSS is 1.24%. Act only if a listed version of An unconstrained memory consumption is installed.

Which versions are affected?

Compare what you have installed with redhat/openshift container platform 4.11; redhat/openshift container platform 4.12; redhat/openshift container platform for power 4.10; redhat/openshift container platform for power 4.9. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-770: Allocation of Resources Without Limits or Throttling. EPSS 1.24%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Keycloak security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Dec 14, 2023 · Monitored products — high

    Detected

    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

  2. Sep 22, 2026 · Monitored products — high

    Updated

    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

Sources

  • CVE.orgVulnerability recordCVE-2023-6563

    Official CVE identifier

    cve.org
  • Monitored products — highVendor advisoryCVE-2023-6563

    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

    nvd.nist.gov

References

Freshness

Last verified in this catalog Nov 6, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • CVE.orgNov 4, 2026
  • Monitored products — highNov 3, 2026