{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-18209", "assignerOrgId": "53f830b8-0a3f-465b-8143-3b8a9948e749", "state": "PUBLISHED", "assignerShortName": "redhat", "dateReserved": "2026-07-29T08:19:43.641Z", "datePublished": "2026-07-31T07:08:31.373Z", "dateUpdated": "2026-07-31T07:08:31.373Z"}, "containers": {"cna": {"title": "Keycloak-services: keycloak-services: oidc redirect_uri fragment bypass in http parameter pollution check", "metrics": [{"other": {"content": {"value": "Low", "namespace": "https://access.redhat.com/security/updates/classification/"}, "type": "Red Hat severity rating"}}, {"cvssV3_1": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 3.4, "baseSeverity": "LOW", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "CHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:N/I:L/A:N", "version": "3.1"}, "format": "CVSS"}], "descriptions": [{"lang": "en", "value": "A flaw was found in the keycloak-services component of Keycloak, which handles OpenID Connect (OIDC) authentication flows. The issue occurs because the security check designed to prevent HTTP parameter pollution only inspects the query portion of a redirect URL and ignores the fragment portion. When a client is configured with a wildcard redirect URI, an attacker can use this to inject duplicate security parameters into the login response. If a client application is not configured correctly, it might trust the attacker's injected data instead of the real security information from Keycloak, leading to session fixation or account confusion."}], "affected": [{"vendor": "Red Hat", "product": "Red Hat Build of Keycloak", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "keycloak-services", "defaultStatus": "affected", "cpes": ["cpe:/a:redhat:build_keycloak:"]}, {"vendor": "Red Hat", "product": "Red Hat Build of Keycloak", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "rhbk-keycloak-rhel9/rhbk-keycloak-rhel9", "defaultStatus": "affected", "cpes": ["cpe:/a:redhat:build_keycloak:"]}, {"vendor": "Red Hat", "product": "Red Hat Build of Keycloak", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "rhbk-openshift-rhel9/rhbk-openshift-rhel9", "defaultStatus": "affected", "cpes": ["cpe:/a:redhat:build_keycloak:"]}, {"vendor": "Red Hat", "product": "Red Hat Data Grid 8", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "keycloak-services", "defaultStatus": "unaffected", "cpes": ["cpe:/a:redhat:jboss_data_grid:8"]}, {"vendor": "Red Hat", "product": "Red Hat JBoss Enterprise Application Platform Expansion Pack", "collectionURL": "https://access.redhat.com/jbossnetwork/restricted/listSoftware.html", "packageName": "keycloak-services", "defaultStatus": "unaffected", "cpes": ["cpe:/a:redhat:jbosseapxp"]}, {"vendor": "Red Hat", "product": "Red Hat Single Sign-On 7", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "keycloak-services", "defaultStatus": "unaffected", "cpes": ["cpe:/a:redhat:red_hat_single_sign_on:7"]}], "references": [{"url": "https://access.redhat.com/security/cve/CVE-2026-18209", "tags": ["vdb-entry", "x_refsource_REDHAT"]}, {"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2508305", "name": "RHBZ#2508305", "tags": ["issue-tracking", "x_refsource_REDHAT"]}], "datePublic": "2026-07-28T13:13:11.000Z", "problemTypes": [{"descriptions": [{"cweId": "CWE-1288", "description": "Improper Validation of Consistency within Input", "lang": "en", "type": "CWE"}]}], "x_redhatCweChain": "CWE-1288: Improper Validation of Consistency within Input", "workarounds": [{"lang": "en", "value": "Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability."}], "timeline": [{"lang": "en", "time": "2026-07-28T13:13:11.000Z", "value": "Reported to Red Hat."}, {"lang": "en", "time": "2026-07-28T13:13:11.000Z", "value": "Made public."}], "credits": [{"lang": "en", "value": "Red Hat would like to thank default-cybe for reporting this issue."}], "providerMetadata": {"orgId": "53f830b8-0a3f-465b-8143-3b8a9948e749", "shortName": "redhat", "dateUpdated": "2026-07-31T07:08:31.373Z"}, "x_generator": {"engine": "cvelib 1.8.0"}}}}

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