CVE-2023-6563

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    CVE-2023-6563

    Published: 14 Dec 2023Last Modified: 23 Sept 2026

    Summary: Keycloak: offline session token dos

    Details: 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.

    References: https://access.redhat.com/downloads/content/package-browser/, https://access.redhat.com/jbossnetwork/restricted/listSoftware.html, https://catalog.redhat.com/software/containers/, https://access.redhat.com/errata/RHSA-2023:7854, https://access.redhat.com/errata/RHSA-2023:7855, https://access.redhat.com/errata/RHSA-2023:7856, https://access.redhat.com/errata/RHSA-2023:7857, https://access.redhat.com/errata/RHSA-2023:7858, https://access.redhat.com/security/cve/CVE-2023-6563, https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/6xxx/CVE-2023-6563.json, https://nvd.nist.gov/vuln/detail/CVE-2023-6563, https://bugzilla.redhat.com/show_bug.cgi?id=2253308, https://github.com/keycloak/keycloak/issues/13340

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: GIT

    Events:

    Introduced- 0
    Fixed -315f02483279cdaa2634742c039b4cf8111d18ef

    Affected versions

    2.4.0.Test

    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
    CVE-2023-6563 | CVE-DB