CVE-2023-6563 (GCVE-0-2023-6563)

Vulnerability from cvelistv5 – Published: 2023-12-14 18:01 – Updated: 2026-09-22 03:27
VLAI
Title
Keycloak: offline session token dos
Summary
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.
Severity
7.7 (High)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
CWE
  • CWE-770 - Allocation of Resources Without Limits or Throttling
Assigner
redhat CNA under the redhat root
CNA scorecard B 82/100 over 1212 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Red Hat Red Hat Single Sign-On 7.6 for RHEL 7 Unaffected: 0:18.0.11-2.redhat_00003.1.el7sso , < * (rpm)
    cpe:/a:redhat:red_hat_single_sign_on:7.6::el7
Create a notification for this product.
Red Hat Red Hat Single Sign-On 7.6 for RHEL 8 Unaffected: 0:18.0.11-2.redhat_00003.1.el8sso , < * (rpm)
    cpe:/a:redhat:red_hat_single_sign_on:7.6::el8
Create a notification for this product.
Red Hat Red Hat Single Sign-On 7.6 for RHEL 9 Unaffected: 0:18.0.11-2.redhat_00003.1.el9sso , < * (rpm)
    cpe:/a:redhat:red_hat_single_sign_on:7.6::el9
Create a notification for this product.
Red Hat RHEL-8 based Middleware Containers Unaffected: 7.6-38 , < * (rpm)
    cpe:/a:redhat:rhosemc:1.0::el8
Create a notification for this product.
Red Hat RHEL-8 based Middleware Containers Unaffected: 7.6.6-2 , < * (rpm)
    cpe:/a:redhat:rhosemc:1.0::el8
Create a notification for this product.
Red Hat Single Sign-On 7.6.6     cpe:/a:redhat:red_hat_single_sign_on:7.6
Create a notification for this product.
Red Hat Red Hat Build of Keycloak     cpe:/a:redhat:build_keycloak:
Create a notification for this product.
Date Public
2023-12-14 00:00
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-02T08:35:14.663Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "name": "RHSA-2023:7854",
            "tags": [
              "vendor-advisory",
              "x_refsource_REDHAT",
              "x_transferred"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2023:7854"
          },
          {
            "name": "RHSA-2023:7855",
            "tags": [
              "vendor-advisory",
              "x_refsource_REDHAT",
              "x_transferred"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2023:7855"
          },
          {
            "name": "RHSA-2023:7856",
            "tags": [
              "vendor-advisory",
              "x_refsource_REDHAT",
              "x_transferred"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2023:7856"
          },
          {
            "name": "RHSA-2023:7857",
            "tags": [
              "vendor-advisory",
              "x_refsource_REDHAT",
              "x_transferred"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2023:7857"
          },
          {
            "name": "RHSA-2023:7858",
            "tags": [
              "vendor-advisory",
              "x_refsource_REDHAT",
              "x_transferred"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2023:7858"
          },
          {
            "tags": [
              "vdb-entry",
              "x_refsource_REDHAT",
              "x_transferred"
            ],
            "url": "https://access.redhat.com/security/cve/CVE-2023-6563"
          },
          {
            "name": "RHBZ#2253308",
            "tags": [
              "issue-tracking",
              "x_refsource_REDHAT",
              "x_transferred"
            ],
            "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2253308"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://github.com/keycloak/keycloak/issues/13340"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/a:redhat:red_hat_single_sign_on:7.6::el7"
          ],
          "defaultStatus": "affected",
          "packageName": "rh-sso7-keycloak",
          "product": "Red Hat Single Sign-On 7.6 for RHEL 7",
          "vendor": "Red Hat",
          "versions": [
            {
              "lessThan": "*",
              "status": "unaffected",
              "version": "0:18.0.11-2.redhat_00003.1.el7sso",
              "versionType": "rpm"
            }
          ]
        },
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/a:redhat:red_hat_single_sign_on:7.6::el8"
          ],
          "defaultStatus": "affected",
          "packageName": "rh-sso7-keycloak",
          "product": "Red Hat Single Sign-On 7.6 for RHEL 8",
          "vendor": "Red Hat",
          "versions": [
            {
              "lessThan": "*",
              "status": "unaffected",
              "version": "0:18.0.11-2.redhat_00003.1.el8sso",
              "versionType": "rpm"
            }
          ]
        },
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/a:redhat:red_hat_single_sign_on:7.6::el9"
          ],
          "defaultStatus": "affected",
          "packageName": "rh-sso7-keycloak",
          "product": "Red Hat Single Sign-On 7.6 for RHEL 9",
          "vendor": "Red Hat",
          "versions": [
            {
              "lessThan": "*",
              "status": "unaffected",
              "version": "0:18.0.11-2.redhat_00003.1.el9sso",
              "versionType": "rpm"
            }
          ]
        },
        {
          "collectionURL": "https://catalog.redhat.com/software/containers/",
          "cpes": [
            "cpe:/a:redhat:rhosemc:1.0::el8"
          ],
          "defaultStatus": "affected",
          "packageName": "rh-sso-7/sso76-openshift-rhel8",
          "product": "RHEL-8 based Middleware Containers",
          "vendor": "Red Hat",
          "versions": [
            {
              "lessThan": "*",
              "status": "unaffected",
              "version": "7.6-38",
              "versionType": "rpm"
            }
          ]
        },
        {
          "collectionURL": "https://catalog.redhat.com/software/containers/",
          "cpes": [
            "cpe:/a:redhat:rhosemc:1.0::el8"
          ],
          "defaultStatus": "affected",
          "packageName": "rh-sso-7/sso7-rhel8-operator-bundle",
          "product": "RHEL-8 based Middleware Containers",
          "vendor": "Red Hat",
          "versions": [
            {
              "lessThan": "*",
              "status": "unaffected",
              "version": "7.6.6-2",
              "versionType": "rpm"
            }
          ]
        },
        {
          "collectionURL": "https://access.redhat.com/jbossnetwork/restricted/listSoftware.html",
          "cpes": [
            "cpe:/a:redhat:red_hat_single_sign_on:7.6"
          ],
          "defaultStatus": "unaffected",
          "packageName": "rh-sso7-keycloak",
          "product": "Single Sign-On 7.6.6",
          "vendor": "Red Hat"
        },
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/a:redhat:build_keycloak:"
          ],
          "defaultStatus": "unaffected",
          "packageName": "keycloak-core",
          "product": "Red Hat Build of Keycloak",
          "vendor": "Red Hat"
        }
      ],
      "datePublic": "2023-12-14T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "An unconstrained memory consumption vulnerability was discovered in Keycloak. It can be triggered in environments which have millions of offline tokens (\u003e 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."
        }
      ],
      "metrics": [
        {
          "other": {
            "content": {
              "namespace": "https://access.redhat.com/security/updates/classification/",
              "value": "Important"
            },
            "type": "Red Hat severity rating"
          }
        },
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 7.7,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "LOW",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H",
            "version": "3.1"
          },
          "format": "CVSS"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-770",
              "description": "Allocation of Resources Without Limits or Throttling",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-22T03:27:59.665Z",
        "orgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
        "shortName": "redhat"
      },
      "references": [
        {
          "name": "RHSA-2023:7854",
          "tags": [
            "vendor-advisory",
            "x_refsource_REDHAT"
          ],
          "url": "https://access.redhat.com/errata/RHSA-2023:7854"
        },
        {
          "name": "RHSA-2023:7855",
          "tags": [
            "vendor-advisory",
            "x_refsource_REDHAT"
          ],
          "url": "https://access.redhat.com/errata/RHSA-2023:7855"
        },
        {
          "name": "RHSA-2023:7856",
          "tags": [
            "vendor-advisory",
            "x_refsource_REDHAT"
          ],
          "url": "https://access.redhat.com/errata/RHSA-2023:7856"
        },
        {
          "name": "RHSA-2023:7857",
          "tags": [
            "vendor-advisory",
            "x_refsource_REDHAT"
          ],
          "url": "https://access.redhat.com/errata/RHSA-2023:7857"
        },
        {
          "name": "RHSA-2023:7858",
          "tags": [
            "vendor-advisory",
            "x_refsource_REDHAT"
          ],
          "url": "https://access.redhat.com/errata/RHSA-2023:7858"
        },
        {
          "tags": [
            "vdb-entry",
            "x_refsource_REDHAT"
          ],
          "url": "https://access.redhat.com/security/cve/CVE-2023-6563"
        },
        {
          "name": "RHBZ#2253308",
          "tags": [
            "issue-tracking",
            "x_refsource_REDHAT"
          ],
          "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2253308"
        },
        {
          "url": "https://github.com/keycloak/keycloak/issues/13340"
        }
      ],
      "timeline": [
        {
          "lang": "en",
          "time": "2023-12-06T00:00:00.000Z",
          "value": "Reported to Red Hat."
        },
        {
          "lang": "en",
          "time": "2023-12-14T00:00:00.000Z",
          "value": "Made public."
        }
      ],
      "title": "Keycloak: offline session token dos",
      "workarounds": [
        {
          "lang": "en",
          "value": "There are three main options to prevent exploitation:\n1) If you are using a reverse proxy, block the consents URL.\n2) This option is less effective: remove the consents application tab from the account console theme.\n3) This option has a significant negative impact on end users: entirely disable offline user profiles."
        }
      ],
      "x_generator": {
        "engine": "cvelib 1.8.0"
      },
      "x_redhatCweChain": "CWE-770: Allocation of Resources Without Limits or Throttling"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
    "assignerShortName": "redhat",
    "cveId": "CVE-2023-6563",
    "datePublished": "2023-12-14T18:01:26.005Z",
    "dateReserved": "2023-12-06T18:47:35.594Z",
    "dateUpdated": "2026-09-22T03:27:59.665Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2023-6563",
      "date": "2026-11-13",
      "epss": "0.01239",
      "percentile": "0.69602"
    },
    "fkie_nvd": {
      "configurations": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:redhat:keycloak:*:*:*:*:*:*:*:*",
                  "matchCriteriaId": "DD663F41-3B6D-4AF0-9ABA-1F3BF292C632",
                  "versionEndExcluding": "21.0.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        },
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:redhat:single_sign-on:7.6:*:*:*:*:*:*:*",
                  "matchCriteriaId": "2DEC61BC-E699-456E-99B6-C049F2A5F23F",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            },
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*",
                  "matchCriteriaId": "142AD0DD-4CF3-4D74-9442-459CE3347E3A",
                  "vulnerable": false
                },
                {
                  "criteria": "cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*",
                  "matchCriteriaId": "F4CFF558-3C47-480D-A2F0-BABF26042943",
                  "vulnerable": false
                },
                {
                  "criteria": "cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*",
                  "matchCriteriaId": "7F6FB57C-2BC7-487C-96DD-132683AEB35D",
                  "vulnerable": false
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ],
          "operator": "AND"
        },
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:redhat:single_sign-on:-:*:*:*:text-only:*:*:*",
                  "matchCriteriaId": "341E6313-20D5-44CB-9719-B20585DC5AD6",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        },
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:redhat:openshift_container_platform:4.11:*:*:*:*:*:*:*",
                  "matchCriteriaId": "EA983F8C-3A06-450A-AEFF-9429DE9A3454",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:a:redhat:openshift_container_platform:4.12:*:*:*:*:*:*:*",
                  "matchCriteriaId": "40449571-22F8-44FA-B57B-B43F71AB25E2",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            },
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*",
                  "matchCriteriaId": "F4CFF558-3C47-480D-A2F0-BABF26042943",
                  "vulnerable": false
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ],
          "operator": "AND"
        },
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:redhat:openshift_container_platform_for_power:4.9:*:*:*:*:*:*:*",
                  "matchCriteriaId": "30E2CF79-2D56-48AB-952E-5DDAFE471073",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:a:redhat:openshift_container_platform_for_power:4.10:*:*:*:*:*:*:*",
                  "matchCriteriaId": "54E24055-813B-4E6D-94B7-FAD5F78B8537",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            },
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*",
                  "matchCriteriaId": "F4CFF558-3C47-480D-A2F0-BABF26042943",
                  "vulnerable": false
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ],
          "operator": "AND"
        },
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:redhat:openshift_container_platform_for_ibm_linuxone:4.9:*:*:*:*:*:*:*",
                  "matchCriteriaId": "8C519B1A-1CD6-426C-9339-F28E4FEF581B",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:a:redhat:openshift_container_platform_for_ibm_linuxone:4.10:*:*:*:*:*:*:*",
                  "matchCriteriaId": "91EE3858-A648-44B4-B282-8F808D88D3B9",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            },
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*",
                  "matchCriteriaId": "F4CFF558-3C47-480D-A2F0-BABF26042943",
                  "vulnerable": false
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ],
          "operator": "AND"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "An unconstrained memory consumption vulnerability was discovered in Keycloak. It can be triggered in environments which have millions of offline tokens (\u003e 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."
        },
        {
          "lang": "es",
          "value": "Se descubri\u00f3 una vulnerabilidad de consumo de memoria sin restricciones en Keycloak. Se puede activar en entornos que tienen millones de tokens fuera de l\u00ednea (\u0026gt; 500.000 usuarios, cada uno con al menos 2 sesiones guardadas). Si un atacante crea dos o m\u00e1s sesiones de usuario y luego abre la pesta\u00f1a \"consentimientos\" de la interfaz de usuario del administrador, la interfaz de usuario intenta cargar una gran cantidad de sesiones de clientes fuera de l\u00ednea, lo que genera un consumo excesivo de memoria y CPU, lo que potencialmente podr\u00eda bloquear todo el sistema."
        }
      ],
      "id": "CVE-2023-6563",
      "lastModified": "2024-11-21T08:44:06.483",
      "metrics": {
        "cvssMetricV31": [
          {
            "cvssData": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "HIGH",
              "baseScore": 7.7,
              "baseSeverity": "HIGH",
              "confidentialityImpact": "NONE",
              "integrityImpact": "NONE",
              "privilegesRequired": "LOW",
              "scope": "CHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H",
              "version": "3.1"
            },
            "exploitabilityScore": 3.1,
            "impactScore": 4.0,
            "source": "secalert@redhat.com",
            "type": "Secondary"
          },
          {
            "cvssData": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "HIGH",
              "baseScore": 7.7,
              "baseSeverity": "HIGH",
              "confidentialityImpact": "NONE",
              "integrityImpact": "NONE",
              "privilegesRequired": "LOW",
              "scope": "CHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H",
              "version": "3.1"
            },
            "exploitabilityScore": 3.1,
            "impactScore": 4.0,
            "source": "nvd@nist.gov",
            "type": "Primary"
          }
        ]
      },
      "published": "2023-12-14T18:15:45.540",
      "references": [
        {
          "source": "secalert@redhat.com",
          "tags": [
            "Vendor Advisory"
          ],
          "url": "https://access.redhat.com/errata/RHSA-2023:7854"
        },
        {
          "source": "secalert@redhat.com",
          "tags": [
            "Vendor Advisory"
          ],
          "url": "https://access.redhat.com/errata/RHSA-2023:7855"
        },
        {
          "source": "secalert@redhat.com",
          "tags": [
            "Vendor Advisory"
          ],
          "url": "https://access.redhat.com/errata/RHSA-2023:7856"
        },
        {
          "source": "secalert@redhat.com",
          "tags": [
            "Exploit"
          ],
          "url": "https://access.redhat.com/errata/RHSA-2023:7857"
        },
        {
          "source": "secalert@redhat.com",
          "tags": [
            "Vendor Advisory"
          ],
          "url": "https://access.redhat.com/errata/RHSA-2023:7858"
        },
        {
          "source": "secalert@redhat.com",
          "tags": [
            "Vendor Advisory"
          ],
          "url": "https://access.redhat.com/security/cve/CVE-2023-6563"
        },
        {
          "source": "secalert@redhat.com",
          "tags": [
            "Issue Tracking"
          ],
          "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2253308"
        },
        {
          "source": "secalert@redhat.com",
          "tags": [
            "Issue Tracking"
          ],
          "url": "https://github.com/keycloak/keycloak/issues/13340"
        },
        {
          "source": "af854a3a-2127-422b-91ae-364da2661108",
          "tags": [
            "Vendor Advisory"
          ],
          "url": "https://access.redhat.com/errata/RHSA-2023:7854"
        },
        {
          "source": "af854a3a-2127-422b-91ae-364da2661108",
          "tags": [
            "Vendor Advisory"
          ],
          "url": "https://access.redhat.com/errata/RHSA-2023:7855"
        },
        {
          "source": "af854a3a-2127-422b-91ae-364da2661108",
          "tags": [
            "Vendor Advisory"
          ],
          "url": "https://access.redhat.com/errata/RHSA-2023:7856"
        },
        {
          "source": "af854a3a-2127-422b-91ae-364da2661108",
          "tags": [
            "Exploit"
          ],
          "url": "https://access.redhat.com/errata/RHSA-2023:7857"
        },
        {
          "source": "af854a3a-2127-422b-91ae-364da2661108",
          "tags": [
            "Vendor Advisory"
          ],
          "url": "https://access.redhat.com/errata/RHSA-2023:7858"
        },
        {
          "source": "af854a3a-2127-422b-91ae-364da2661108",
          "tags": [
            "Vendor Advisory"
          ],
          "url": "https://access.redhat.com/security/cve/CVE-2023-6563"
        },
        {
          "source": "af854a3a-2127-422b-91ae-364da2661108",
          "tags": [
            "Issue Tracking"
          ],
          "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2253308"
        },
        {
          "source": "af854a3a-2127-422b-91ae-364da2661108",
          "tags": [
            "Issue Tracking"
          ],
          "url": "https://github.com/keycloak/keycloak/issues/13340"
        }
      ],
      "sourceIdentifier": "secalert@redhat.com",
      "vulnStatus": "Modified",
      "weaknesses": [
        {
          "description": [
            {
              "lang": "en",
              "value": "CWE-770"
            }
          ],
          "source": "secalert@redhat.com",
          "type": "Secondary"
        },
        {
          "description": [
            {
              "lang": "en",
              "value": "CWE-770"
            }
          ],
          "source": "nvd@nist.gov",
          "type": "Primary"
        }
      ]
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
                "cpes": [
                  "cpe:/a:redhat:red_hat_single_sign_on:7.6::el7"
                ],
                "defaultStatus": "affected",
                "packageName": "rh-sso7-keycloak",
                "product": "Red Hat Single Sign-On 7.6 for RHEL 7",
                "vendor": "Red Hat",
                "versions": [
                  {
                    "lessThan": "*",
                    "status": "unaffected",
                    "version": "0:18.0.11-2.redhat_00003.1.el7sso",
                    "versionType": "rpm"
                  }
                ]
              },
              {
                "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
                "cpes": [
                  "cpe:/a:redhat:red_hat_single_sign_on:7.6::el8"
                ],
                "defaultStatus": "affected",
                "packageName": "rh-sso7-keycloak",
                "product": "Red Hat Single Sign-On 7.6 for RHEL 8",
                "vendor": "Red Hat",
                "versions": [
                  {
                    "lessThan": "*",
                    "status": "unaffected",
                    "version": "0:18.0.11-2.redhat_00003.1.el8sso",
                    "versionType": "rpm"
                  }
                ]
              },
              {
                "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
                "cpes": [
                  "cpe:/a:redhat:red_hat_single_sign_on:7.6::el9"
                ],
                "defaultStatus": "affected",
                "packageName": "rh-sso7-keycloak",
                "product": "Red Hat Single Sign-On 7.6 for RHEL 9",
                "vendor": "Red Hat",
                "versions": [
                  {
                    "lessThan": "*",
                    "status": "unaffected",
                    "version": "0:18.0.11-2.redhat_00003.1.el9sso",
                    "versionType": "rpm"
                  }
                ]
              },
              {
                "collectionURL": "https://catalog.redhat.com/software/containers/",
                "cpes": [
                  "cpe:/a:redhat:rhosemc:1.0::el8"
                ],
                "defaultStatus": "affected",
                "packageName": "rh-sso-7/sso76-openshift-rhel8",
                "product": "RHEL-8 based Middleware Containers",
                "vendor": "Red Hat",
                "versions": [
                  {
                    "lessThan": "*",
                    "status": "unaffected",
                    "version": "7.6-38",
                    "versionType": "rpm"
                  }
                ]
              },
              {
                "collectionURL": "https://catalog.redhat.com/software/containers/",
                "cpes": [
                  "cpe:/a:redhat:rhosemc:1.0::el8"
                ],
                "defaultStatus": "affected",
                "packageName": "rh-sso-7/sso7-rhel8-operator-bundle",
                "product": "RHEL-8 based Middleware Containers",
                "vendor": "Red Hat",
                "versions": [
                  {
                    "lessThan": "*",
                    "status": "unaffected",
                    "version": "7.6.6-2",
                    "versionType": "rpm"
                  }
                ]
              },
              {
                "collectionURL": "https://access.redhat.com/jbossnetwork/restricted/listSoftware.html",
                "cpes": [
                  "cpe:/a:redhat:red_hat_single_sign_on:7.6"
                ],
                "defaultStatus": "unaffected",
                "packageName": "rh-sso7-keycloak",
                "product": "Single Sign-On 7.6.6",
                "vendor": "Red Hat"
              },
              {
                "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
                "cpes": [
                  "cpe:/a:redhat:build_keycloak:"
                ],
                "defaultStatus": "unaffected",
                "packageName": "keycloak-core",
                "product": "Red Hat Build of Keycloak",
                "vendor": "Red Hat"
              }
            ],
            "source": "secalert@redhat.com"
          }
        ],
        "configurations": [
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:a:redhat:keycloak:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "DD663F41-3B6D-4AF0-9ABA-1F3BF292C632",
                    "versionEndExcluding": "21.0.0",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          },
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:a:redhat:single_sign-on:7.6:*:*:*:*:*:*:*",
                    "matchCriteriaId": "2DEC61BC-E699-456E-99B6-C049F2A5F23F",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              },
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*",
                    "matchCriteriaId": "142AD0DD-4CF3-4D74-9442-459CE3347E3A",
                    "vulnerable": false
                  },
                  {
                    "criteria": "cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*",
                    "matchCriteriaId": "F4CFF558-3C47-480D-A2F0-BABF26042943",
                    "vulnerable": false
                  },
                  {
                    "criteria": "cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*",
                    "matchCriteriaId": "7F6FB57C-2BC7-487C-96DD-132683AEB35D",
                    "vulnerable": false
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ],
            "operator": "AND"
          },
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:a:redhat:single_sign-on:-:*:*:*:text-only:*:*:*",
                    "matchCriteriaId": "341E6313-20D5-44CB-9719-B20585DC5AD6",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          },
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:a:redhat:openshift_container_platform:4.11:*:*:*:*:*:*:*",
                    "matchCriteriaId": "EA983F8C-3A06-450A-AEFF-9429DE9A3454",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:a:redhat:openshift_container_platform:4.12:*:*:*:*:*:*:*",
                    "matchCriteriaId": "40449571-22F8-44FA-B57B-B43F71AB25E2",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              },
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*",
                    "matchCriteriaId": "F4CFF558-3C47-480D-A2F0-BABF26042943",
                    "vulnerable": false
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ],
            "operator": "AND"
          },
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:a:redhat:openshift_container_platform_for_power:4.9:*:*:*:*:*:*:*",
                    "matchCriteriaId": "30E2CF79-2D56-48AB-952E-5DDAFE471073",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:a:redhat:openshift_container_platform_for_power:4.10:*:*:*:*:*:*:*",
                    "matchCriteriaId": "54E24055-813B-4E6D-94B7-FAD5F78B8537",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              },
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*",
                    "matchCriteriaId": "F4CFF558-3C47-480D-A2F0-BABF26042943",
                    "vulnerable": false
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ],
            "operator": "AND"
          },
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:a:redhat:openshift_container_platform_for_ibm_linuxone:4.9:*:*:*:*:*:*:*",
                    "matchCriteriaId": "8C519B1A-1CD6-426C-9339-F28E4FEF581B",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:a:redhat:openshift_container_platform_for_ibm_linuxone:4.10:*:*:*:*:*:*:*",
                    "matchCriteriaId": "91EE3858-A648-44B4-B282-8F808D88D3B9",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              },
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*",
                    "matchCriteriaId": "F4CFF558-3C47-480D-A2F0-BABF26042943",
                    "vulnerable": false
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ],
            "operator": "AND"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "An unconstrained memory consumption vulnerability was discovered in Keycloak. It can be triggered in environments which have millions of offline tokens (\u003e 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."
          },
          {
            "lang": "es",
            "value": "Se descubri\u00f3 una vulnerabilidad de consumo de memoria sin restricciones en Keycloak. Se puede activar en entornos que tienen millones de tokens fuera de l\u00ednea (\u0026gt; 500.000 usuarios, cada uno con al menos 2 sesiones guardadas). Si un atacante crea dos o m\u00e1s sesiones de usuario y luego abre la pesta\u00f1a \"consentimientos\" de la interfaz de usuario del administrador, la interfaz de usuario intenta cargar una gran cantidad de sesiones de clientes fuera de l\u00ednea, lo que genera un consumo excesivo de memoria y CPU, lo que potencialmente podr\u00eda bloquear todo el sistema."
          }
        ],
        "id": "CVE-2023-6563",
        "lastModified": "2026-09-22T04:17:56.693",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 7.7,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "NONE",
                "integrityImpact": "NONE",
                "privilegesRequired": "LOW",
                "scope": "CHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 3.1,
              "impactScore": 4.0,
              "source": "secalert@redhat.com",
              "type": "Secondary"
            },
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 7.7,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "NONE",
                "integrityImpact": "NONE",
                "privilegesRequired": "LOW",
                "scope": "CHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 3.1,
              "impactScore": 4.0,
              "source": "nvd@nist.gov",
              "type": "Primary"
            }
          ]
        },
        "published": "2023-12-14T18:15:45.540",
        "references": [
          {
            "source": "secalert@redhat.com",
            "tags": [
              "Vendor Advisory"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2023:7854"
          },
          {
            "source": "secalert@redhat.com",
            "tags": [
              "Vendor Advisory"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2023:7855"
          },
          {
            "source": "secalert@redhat.com",
            "tags": [
              "Vendor Advisory"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2023:7856"
          },
          {
            "source": "secalert@redhat.com",
            "tags": [
              "Exploit"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2023:7857"
          },
          {
            "source": "secalert@redhat.com",
            "tags": [
              "Vendor Advisory"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2023:7858"
          },
          {
            "source": "secalert@redhat.com",
            "tags": [
              "Vendor Advisory"
            ],
            "url": "https://access.redhat.com/security/cve/CVE-2023-6563"
          },
          {
            "source": "secalert@redhat.com",
            "tags": [
              "Issue Tracking"
            ],
            "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2253308"
          },
          {
            "source": "secalert@redhat.com",
            "tags": [
              "Issue Tracking"
            ],
            "url": "https://github.com/keycloak/keycloak/issues/13340"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Vendor Advisory"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2023:7854"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Vendor Advisory"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2023:7855"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Vendor Advisory"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2023:7856"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Exploit"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2023:7857"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Vendor Advisory"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2023:7858"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Vendor Advisory"
            ],
            "url": "https://access.redhat.com/security/cve/CVE-2023-6563"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Issue Tracking"
            ],
            "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2253308"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Issue Tracking"
            ],
            "url": "https://github.com/keycloak/keycloak/issues/13340"
          }
        ],
        "sourceIdentifier": "secalert@redhat.com",
        "vulnStatus": "Modified",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-770"
              }
            ],
            "source": "secalert@redhat.com",
            "type": "Secondary"
          },
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-770"
              }
            ],
            "source": "nvd@nist.gov",
            "type": "Primary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Important",
      "current_release_date": "2026-09-22T03:27:56+00:00",
      "cve": "CVE-2023-6563",
      "id": "CVE-2023-6563",
      "initial_release_date": "2023-12-14T00:00:00+00:00",
      "product_status:fixed": "14",
      "product_status:known_not_affected": "1",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "keycloak: offline session token DoS",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2023/cve-2023-6563.json",
      "version": "3"
    }
  }
}


Workarounds

CNA · redhat
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.

Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON
How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

Loading timeline…




    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.