Open Forms possible to view submission details of other people than intended

{
  "id": "32986365d98c1843993669f59d68b9d7ecb598c2b83a8c32c95ae131bbcccb1d",
  "url": "https://osv.dev/vulnerability/CVE-2026-28803",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Open Forms possible to view submission details of other people than intended",
    "summary": "Open Forms allows users create and publish smart forms. Prior to 3.3.13 and 3.4.5, to be able to cosign, the cosigner receives an e-mail with instructions or a deep-link to start the cosign flow. The submission reference is communicated so that the user can retrieve the submission to be cosigned. Attackers can guess a code or modify the received code to look up arbitrary submissions, after logging in (with DigiD/eHerkenning/... depending on form configuration). This vulnerability is fixed in 3.3.13 and 3.4.5.",
    "evidence": "osv:CVE-2026-28803",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-28803",
      "aliases": [
        "CVE-2026-28803",
        "GHSA-2g49-rfm6-5qj5"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/open-formulieren/open-forms",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "70ce5fae45b07d4625e7ae6b0a49c1498f23cd3e"
                },
                {
                  "introduced": "6187ccc60ad99af2da8076355f44a80886bcd808"
                },
                {
                  "fixed": "b7372aae0419ad3881e0792fd3c7dacd991bb90d"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:maykinmedia:open_forms:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "3.3.13"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:maykinmedia:open_forms:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "3.4.0"
                      },
                      {
                        "fixed": "3.4.5"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "3.4.4",
            "3.3.12",
            "3.4.3",
            "3.4.2",
            "3.3.11",
            "3.4.1",
            "3.4.0",
            "3.3.10",
            "3.3.9",
            "3.3.8",
            "3.3.7",
            "3.3.6",
            "3.3.5",
            "3.3.4",
            "3.3.3",
            "3.3.2",
            "3.3.1",
            "3.3.1-alpha.0",
            "3.3.0",
            "3.3.0-rc.0",
            "3.3.0-alpha.1",
            "3.3.0-alpha.0",
            "3.2.0",
            "3.2.0-alpha.1",
            "3.2.0-alpha.0",
            "3.1.0",
            "3.1.0-alpha.1",
            "3.1.0-alpha.0",
            "3.0.1",
            "3.0.0",
            "3.0.0-rc.1",
            "3.0.0-rc.0",
            "3.0.0-alpha.0",
            "2.8.0-beta.0",
            "2.8.0-alpha.0",
            "2.7.0",
            "2.7.0-alpha.0",
            "2.6.0",
            "2.6.0-alpha.0",
            "2.5.0",
            "2.5.0-alpha.0",
            "2.4.0",
            "2.4.0-alpha.0",
            "2.3.0-haalcentraalhr.0",
            "2.3.0",
            "2.3.0-hodm.2",
            "1.5.0-hodm.2",
            "1.5.0-hodm.1",
            "2.3.0-hodm.1",
            "2.3.0-alpha.1+hodm",
            "2.3.0-alpha.0",
            "2.2.1-beta.0",
            "2.1.0-alpha.2",
            "2.1.0-alpha.0",
            "2.0.0-beta.0",
            "perf-profiling-before-logic-refactor",
            "revert_dh",
            "1.0.0",
            "1.0.0-rc.4",
            "1.0.0-rc.3",
            "1.0.0-rc.2",
            "1.0.0-rc.1",
            "1.0.0-rc.0",
            "sprint-11",
            "sprint-10",
            "sprint-9",
            "sprint-8",
            "sprint-7",
            "mvp",
            "sprint-6",
            "sprint-5",
            "sprint-4",
            "demodam",
            "POC",
            "tag-push-test",
            "before-sdk",
            "still-functional"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-28803.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:52.335094958Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/28xxx/CVE-2026-28803.json",
        "https://github.com/open-formulieren/open-forms/security/advisories/GHSA-2g49-rfm6-5qj5",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-28803"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-284"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/28xxx/CVE-2026-28803.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-28803",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 521139,
  "published_at": "2026-03-11T15:52:08.464+00:00"
}