High

Keycloak: keycloak: denial of service via specially crafted saml input

Type: advisorySource: Official CVE List1 source record

A flaw was found in Keycloak. A remote, unauthenticated attacker can send a specially crafted XML input to the Security Assertion Markup Language (SAML) endpoint. This malicious input can cause high CPU usage and worker thread starvation, leading to a Denial of Service (DoS) where the server becomes unavailable.

Announced 19 May 2026Source revision 1

Original source ↗

CVE-2026-7307

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-7307

Red Hat build of Keycloak 26.2

Source reference: /containers/cna/affected/1/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat build of Keycloak 26.2

Source reference: /containers/cna/affected/2/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat build of Keycloak 26.2

Source reference: /containers/cna/affected/3/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat build of Keycloak 26.2.16

Source reference: /containers/cna/affected/4/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat build of Keycloak 26.4

Source reference: /containers/cna/affected/5/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat build of Keycloak 26.4

Source reference: /containers/cna/affected/6/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat build of Keycloak 26.4

Source reference: /containers/cna/affected/7/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat build of Keycloak 26.4.12

Source reference: /containers/cna/affected/8/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat Single Sign-On 7.6.13

Source reference: /containers/cna/affected/9/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat Single Sign-On 7.6 for RHEL 7

Source reference: /containers/cna/affected/10/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat Single Sign-On 7.6 for RHEL 8

Source reference: /containers/cna/affected/11/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat Single Sign-On 7.6 for RHEL 9

Source reference: /containers/cna/affected/12/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

RHEL-8 based Middleware Containers

Source reference: /containers/cna/affected/13/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "versions": [
      {
        "status": "affected",
        "version": "0",
        "lessThan": "26.2.16",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "0",
        "lessThan": "26.4.12",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "0",
        "lessThan": "26.6.2",
        "versionType": "semver"
      }
    ],
    "packageName": "keycloak",
    "collectionURL": "https://github.com/keycloak/keycloak",
    "defaultStatus": "unaffected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:build_keycloak:26.2::el9"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat build of Keycloak 26.2",
    "versions": [
      {
        "status": "unaffected",
        "version": "26.2.16-1",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "rhbk/keycloak-operator-bundle",
    "collectionURL": "https://catalog.redhat.com/software/containers/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:build_keycloak:26.2::el9"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat build of Keycloak 26.2",
    "versions": [
      {
        "status": "unaffected",
        "version": "26.2-21",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "rhbk/keycloak-rhel9",
    "collectionURL": "https://catalog.redhat.com/software/containers/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:build_keycloak:26.2::el9"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat build of Keycloak 26.2",
    "versions": [
      {
        "status": "unaffected",
        "version": "26.2-21",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "rhbk/keycloak-rhel9-operator",
    "collectionURL": "https://catalog.redhat.com/software/containers/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:build_keycloak:26.2::el9"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat build of Keycloak 26.2.16",
    "packageName": "rhbk/keycloak-rhel9",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "unaffected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:build_keycloak:26.4::el9"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat build of Keycloak 26.4",
    "versions": [
      {
        "status": "unaffected",
        "version": "26.4.12-1",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "rhbk/keycloak-operator-bundle",
    "collectionURL": "https://catalog.redhat.com/software/containers/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:build_keycloak:26.4::el9"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat build of Keycloak 26.4",
    "versions": [
      {
        "status": "unaffected",
        "version": "26.4-17",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "rhbk/keycloak-rhel9",
    "collectionURL": "https://catalog.redhat.com/software/containers/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:build_keycloak:26.4::el9"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat build of Keycloak 26.4",
    "versions": [
      {
        "status": "unaffected",
        "version": "26.4-17",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "rhbk/keycloak-rhel9-operator",
    "collectionURL": "https://catalog.redhat.com/software/containers/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:build_keycloak:26.4::el9"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat build of Keycloak 26.4.12",
    "packageName": "rhbk/keycloak-rhel9",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "unaffected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:red_hat_single_sign_on:7.6"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Single Sign-On 7.6.13",
    "packageName": "keycloak-services",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "unaffected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:red_hat_single_sign_on:7.6::el7"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Single Sign-On 7.6 for RHEL 7",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:18.0.20-1.redhat_00001.1.el7sso",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "rh-sso7-keycloak",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:red_hat_single_sign_on:7.6::el8"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Single Sign-On 7.6 for RHEL 8",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:18.0.20-1.redhat_00001.1.el8sso",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "rh-sso7-keycloak",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:red_hat_single_sign_on:7.6::el9"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Single Sign-On 7.6 for RHEL 9",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:18.0.20-1.redhat_00001.1.el9sso",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "rh-sso7-keycloak",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:rhosemc:1.0::el8"
    ],
    "vendor": "Red Hat",
    "product": "RHEL-8 based Middleware Containers",
    "versions": [
      {
        "status": "unaffected",
        "version": "7.6-85",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "rh-sso-7/sso76-openshift-rhel8",
    "collectionURL": "https://catalog.redhat.com/software/containers/",
    "defaultStatus": "affected"
  }
]

Related CVEs: CVE-2026-7307
Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event: #9402 · Revision 1
Added to Heist Feed: Sat, 24 Oct 2026 23:17:23 GMT
Publisher date: Tue, 19 May 2026 10:52:24 GMT

Read the original announcement