CVE-2026-11800

A flaw was found in Keycloak. This JWT algorithm confusion vulnerability in the JWT Authorization Grant flow allows an attacker with valid client credentials to bypass signature verification. By forging an assertion, the attacker can create unauthorized access tokens. This enables the attacker to impersonate any federated user linked to the affected Identity Provider, leading to unauthorized access and potential privilege escalation.

CVSS v3 8.1 HIGH

8.1^/10

CVSS v3 : HIGH

Vector :

Exploitability : 2.8 / Impact : 5.2

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://access.redhat.com/errata/RHSA-2026:30083	Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:30084	Vendor Advisory
https://access.redhat.com/security/cve/CVE-2026-11800	Vendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2487006	Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:30083	Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:30084	Vendor Advisory
https://access.redhat.com/security/cve/CVE-2026-11800	Vendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2487006	Vendor Advisory
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-11800.json	Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:redhat:build_of_keycloak:*:*:*:*:*:*:*:*

History

No history.

Information

Published : 2026-06-25 22:17

Updated : 2026-07-15 02:18

NVD link : CVE-2026-11800

Mitre link : CVE-2026-11800

CVE.ORG link : CVE-2026-11800

JSON object : View

Products Affected

redhat

build_of_keycloak

CWE

CWE-347

Improper Verification of Cryptographic Signature

{"id": "CVE-2026-11800", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-11800", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "total"}], "version": "2.0.3", "timestamp": "2026-06-26T13:03:46.141909Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "secalert@redhat.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 8.1, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}, "impactScore": 5.2, "exploitabilityScore": 2.8}, {"type": "Secondary", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 8.1, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}, "impactScore": 5.2, "exploitabilityScore": 2.8}]}, "affected": [{"source": "secalert@redhat.com", "affectedData": [{"cpes": ["cpe:/a:redhat:build_keycloak:26.6::el9"], "vendor": "Red Hat", "product": "Red Hat build of Keycloak 26.6", "versions": [{"status": "unaffected", "version": "26.6.4-2", "lessThan": "*", "versionType": "rpm"}], "packageName": "rhbk/keycloak-operator-bundle", "collectionURL": "https://catalog.redhat.com/software/containers/", "defaultStatus": "affected"}, {"cpes": ["cpe:/a:redhat:build_keycloak:26.6::el9"], "vendor": "Red Hat", "product": "Red Hat build of Keycloak 26.6", "versions": [{"status": "unaffected", "version": "26.6-8", "lessThan": "*", "versionType": "rpm"}], "packageName": "rhbk/keycloak-rhel9", "collectionURL": "https://catalog.redhat.com/software/containers/", "defaultStatus": "affected"}, {"cpes": ["cpe:/a:redhat:build_keycloak:26.6::el9"], "vendor": "Red Hat", "product": "Red Hat build of Keycloak 26.6", "versions": [{"status": "unaffected", "version": "26.6-8", "lessThan": "*", "versionType": "rpm"}], "packageName": "rhbk/keycloak-rhel9-operator", "collectionURL": "https://catalog.redhat.com/software/containers/", "defaultStatus": "affected"}, {"cpes": ["cpe:/a:redhat:build_keycloak:26.6::el9"], "vendor": "Red Hat", "product": "Red Hat build of Keycloak 26.6.4", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unaffected"}, {"cpes": ["cpe:/a:redhat:build_keycloak:"], "vendor": "Red Hat", "product": "Red Hat Build of Keycloak", "packageName": "rhbk/keycloak-rhel9", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "affected"}, {"cpes": ["cpe:/a:redhat:build_keycloak:"], "vendor": "Red Hat", "product": "Red Hat Build of Keycloak", "packageName": "rhbk-openshift-rhel9/rhbk-openshift-rhel9", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unaffected"}, {"cpes": ["cpe:/a:redhat:jboss_data_grid:8"], "vendor": "Red Hat", "product": "Red Hat Data Grid 8", "packageName": "keycloak-services", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unaffected"}, {"cpes": ["cpe:/a:redhat:jbosseapxp"], "vendor": "Red Hat", "product": "Red Hat JBoss Enterprise Application Platform Expansion Pack", "packageName": "keycloak-services", "collectionURL": "https://access.redhat.com/jbossnetwork/restricted/listSoftware.html", "defaultStatus": "unaffected"}, {"cpes": ["cpe:/a:redhat:red_hat_single_sign_on:7"], "vendor": "Red Hat", "product": "Red Hat Single Sign-On 7", "packageName": "keycloak-services", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unaffected"}]}, {"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "affectedData": [{"cpes": ["cpe:/a:redhat:build_keycloak:26.6::el9"], "vendor": "Red Hat", "product": "Red Hat build of Keycloak 26.6", "versions": [{"status": "unaffected", "version": "26.6.4-2", "lessThan": "*", "versionType": "rpm"}], "packageName": "rhbk/keycloak-operator-bundle", "collectionURL": "https://catalog.redhat.com/software/containers/", "defaultStatus": "affected"}, {"cpes": ["cpe:/a:redhat:build_keycloak:26.6::el9"], "vendor": "Red Hat", "product": "Red Hat build of Keycloak 26.6", "versions": [{"status": "unaffected", "version": "26.6-8", "lessThan": "*", "versionType": "rpm"}], "packageName": "rhbk/keycloak-rhel9", "collectionURL": "https://catalog.redhat.com/software/containers/", "defaultStatus": "affected"}, {"cpes": ["cpe:/a:redhat:build_keycloak:26.6::el9"], "vendor": "Red Hat", "product": "Red Hat build of Keycloak 26.6", "versions": [{"status": "unaffected", "version": "26.6-8", "lessThan": "*", "versionType": "rpm"}], "packageName": "rhbk/keycloak-rhel9-operator", "collectionURL": "https://catalog.redhat.com/software/containers/", "defaultStatus": "affected"}, {"cpes": ["cpe:/a:redhat:build_keycloak:26.6::el9"], "vendor": "Red Hat", "product": "Red Hat build of Keycloak 26.6.4", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unaffected"}, {"cpes": ["cpe:/a:redhat:build_keycloak:"], "vendor": "Red Hat", "product": "Red Hat Build of Keycloak", "packageName": "rhbk/keycloak-rhel9", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "affected"}, {"cpes": ["cpe:/a:redhat:build_keycloak:"], "vendor": "Red Hat", "product": "Red Hat Build of Keycloak", "packageName": "rhbk-openshift-rhel9/rhbk-openshift-rhel9", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unaffected"}, {"cpes": ["cpe:/a:redhat:jboss_data_grid:8"], "vendor": "Red Hat", "product": "Red Hat Data Grid 8", "packageName": "keycloak-services", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unaffected"}, {"cpes": ["cpe:/a:redhat:jbosseapxp"], "vendor": "Red Hat", "product": "Red Hat JBoss Enterprise Application Platform Expansion Pack", "packageName": "keycloak-services", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unaffected"}, {"cpes": ["cpe:/a:redhat:red_hat_single_sign_on:7"], "vendor": "Red Hat", "product": "Red Hat Single Sign-On 7", "packageName": "keycloak-services", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unaffected"}]}], "published": "2026-06-25T22:17:00.473", "references": [{"url": "https://access.redhat.com/errata/RHSA-2026:30083", "tags": ["Vendor Advisory"], "source": "secalert@redhat.com"}, {"url": "https://access.redhat.com/errata/RHSA-2026:30084", "tags": ["Vendor Advisory"], "source": "secalert@redhat.com"}, {"url": "https://access.redhat.com/security/cve/CVE-2026-11800", "tags": ["Vendor Advisory"], "source": "secalert@redhat.com"}, {"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2487006", "tags": ["Vendor Advisory"], "source": "secalert@redhat.com"}, {"url": "https://access.redhat.com/errata/RHSA-2026:30083", "tags": ["Vendor Advisory"], "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}, {"url": "https://access.redhat.com/errata/RHSA-2026:30084", "tags": ["Vendor Advisory"], "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}, {"url": "https://access.redhat.com/security/cve/CVE-2026-11800", "tags": ["Vendor Advisory"], "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}, {"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2487006", "tags": ["Vendor Advisory"], "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}, {"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-11800.json", "tags": ["Vendor Advisory"], "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "secalert@redhat.com", "description": [{"lang": "en", "value": "CWE-347"}]}, {"type": "Secondary", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "description": [{"lang": "en", "value": "CWE-347"}]}], "descriptions": [{"lang": "en", "value": "A flaw was found in Keycloak. This JWT algorithm confusion vulnerability in the JWT Authorization Grant flow allows an attacker with valid client credentials to bypass signature verification. By forging an assertion, the attacker can create unauthorized access tokens. This enables the attacker to impersonate any federated user linked to the affected Identity Provider, leading to unauthorized access and potential privilege escalation."}], "lastModified": "2026-07-15T02:18:03.933", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:redhat:build_of_keycloak:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "EC1CC78D-43C0-4F1E-AC80-6B302F992816", "versionEndExcluding": "26.6.4", "versionStartIncluding": "26.6"}], "operator": "OR"}]}], "sourceIdentifier": "secalert@redhat.com"}