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    CVE-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 excessive memory and CPU consumption which could potentially crash the entire system.

    Published:Dec 14, 2023
    Last Modified:Nov 11, 2025
    EPS:Dec 14, 2023
    EPSS Score:0.00304
    CVSS Score:7.7

    Affected Products

    Vendor
    Redhat
    Product
    Build Keycloak
    Vendor
    Redhat
    Product
    Enterprise Linux
    Vendor
    Redhat
    Product
    Keycloak
    Vendor
    Redhat
    Product
    Openshift Container Platform
    Vendor
    Redhat
    Product
    Openshift Container Platform For Ibm Linuxone
    Vendor
    Redhat
    Product
    Openshift Container Platform For Power
    Vendor
    Redhat
    Product
    Red Hat Single Sign On
    Vendor
    Redhat
    Product
    Rhosemc
    Vendor
    Redhat
    Product
    Single Sign-on

    Exploits

    https://access.redhat.com/errata/RHSA-2023:7857https://access.redhat.com/errata/RHSA-2023:7857

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    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High