OpenAM: Pre-auth Reflected XSS in OAuth2 / OIDC response_mode=form_post via state parameter (FormPostResponse.ftl)

{
  "id": "a62717b717948aa731c91a4dbbdd00631fc17990e544fd976e1a9436ed6c4c6a",
  "url": "https://osv.dev/vulnerability/CVE-2026-44203",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "OpenAM: Pre-auth Reflected XSS in OAuth2 / OIDC response_mode=form_post via state parameter (FormPostResponse.ftl)",
    "summary": "Open Access Management (OpenAM) is an access management solution. Prior to 16.1.1, the OAuth 2.0 and OpenID Connect authorization endpoint does not sufficiently encode user-supplied parameters before FormPostResponse.ftl and checkSession.ftl render them into HTML for the form_post response mode. An unauthenticated attacker can induce a user to open a crafted authorization request and execute script in the OpenAM origin. This issue is fixed in version 16.1.1.",
    "evidence": "osv:CVE-2026-44203",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-44203",
      "aliases": [
        "CVE-2026-44203",
        "GHSA-fq9h-c788-fx73"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:H/VA:N/SC:L/SI:H/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/openidentityplatform/openam",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "fe2271ec119e827b4252cec20293480322a84789"
                },
                {
                  "fixed": "078bd4754905f5130eaa7bbe45f958eaeb7fd0d7"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "16.1.1"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "078bd4754905f5130eaa7bbe45f958eaeb7fd0d7"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "fe2271ec119e827b4252cec20293480322a84789"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "16.1.1"
                  }
                ]
              }
            }
          ],
          "versions": [
            "16.0.6",
            "16.0.5",
            "16.0.4",
            "16.0.3",
            "15.2.2",
            "15.2.1",
            "15.2.0",
            "15.1.6",
            "15.1.5",
            "15.1.4",
            "15.1.3",
            "15.1.2",
            "15.1.1",
            "15.1.0",
            "15.0.4",
            "15.0.3",
            "15.0.2",
            "15.0.1",
            "15.0.0",
            "14.8.4",
            "14.8.3",
            "14.8.2",
            "14.8.1",
            "14.7.4",
            "14.7.3",
            "14.7.2",
            "14.7.1",
            "14.7.0",
            "14.6.6",
            "14.6.5",
            "14.6.4",
            "14.6.3",
            "14.6.2",
            "14.5.4",
            "14.5.3",
            "14.5.2",
            "14.5.1",
            "14.4.2",
            "14.4.1",
            "14.3.1",
            "14.2.2",
            "14.2.1",
            "14.1.17",
            "14.1.16",
            "14.1.13",
            "14.1.12",
            "14.1.11",
            "14.1.10",
            "14.1.9",
            "14.1.8",
            "14.1.7",
            "14.1.6",
            "14.1.5",
            "14.1.4",
            "14.1.3",
            "14.1.2",
            "14.1.1",
            "14.0.6",
            "14.0.5",
            "14.0.4",
            "14.0.3",
            "14.0.2",
            "14.0.1",
            "14.0.0",
            "13.0.0",
            "13.0.0-RC10",
            "13.0.0-RC9",
            "13.0.0-RC8",
            "13.0.0-RC7",
            "13.0.0-RC6",
            "13.0.0-RC5",
            "13.0.0-RC4",
            "13.0.0-RC3",
            "13.0.0-RC2",
            "13.0.0-RC1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-44203.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:45.870702316Z",
      "provider": "osv",
      "references": [
        "https://github.com/OpenIdentityPlatform/OpenAM/releases/tag/16.1.1",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44203.json",
        "https://github.com/OpenIdentityPlatform/OpenAM/security/advisories/GHSA-fq9h-c788-fx73",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-44203",
        "https://github.com/OpenIdentityPlatform/OpenAM/commit/078bd4754905f5130eaa7bbe45f958eaeb7fd0d7"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-79"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44203.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-44203",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 513750,
  "published_at": "2026-09-15T09:48:07.329+00:00"
}