JHipster: Generated Applications Allow Stored XSS via Unrestricted Blob ContentType Opened as Same-Origin Blob

{
  "id": "a98d26928130c34bb778dca172b6656fa7d52695945f3d4925eaf2c1fd242bd4",
  "url": "https://osv.dev/vulnerability/GHSA-9ffp-22j7-56r2",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "JHipster: Generated Applications Allow Stored XSS via Unrestricted Blob ContentType Opened as Same-Origin Blob",
    "summary": "## Summary Applications generated by generator-jhipster v9.2.0 can persist user-controlled Blob ContentType values and later use those values as the MIME type for client-side Blob objects. The shared generated `openFile` helper creates an object URL from the Blob and opens it in a new window. For Blob-bearing entities writable by normal authenticated users, this creates a stored XSS chain: attacker-controlled Blob content and MIME type are stored through the generated REST API, returned to privileged users, and opened as a same-origin Blob document from the generated Angular/React/Vue UI. Exploitability should be confirmed against the generated app’s CSP and target browsers. ## Details The root cause is a trust-boundary failure across generated server and client code. The generated entity REST resource accepts request bodies for entity creation and update. Unless an entity-specific authority is configured, the template omits method-level `@PreAuthorize`, leaving the endpoint available to any authenticated user under the global `/api/**` security rule. The generated DTO/domain/mapper flow stores the companion `ContentType` property as a plain `String` and persists it with the entity Blob data. The relevant templates include `generators/spring-boot/templates/src/main/java/_package_/_entityPackage_/service/dto/_dtoClass_.java.ejs:96-122` and `generators/java/generators/domain/templates/src/main/java/_package_/_entityPackage_/domain/_persistClass_.java.jhi.ejs:124-140`. The gener",
    "evidence": "osv:GHSA-9ffp-22j7-56r2",
    "products": [
      {
        "name": {
          "value": "generator-jhipster",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "9.4.0",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "react-jhipster",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1.1.0",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "GHSA-9ffp-22j7-56r2",
      "aliases": [
        "CVE-2026-107303",
        "GHSA-9ffp-22j7-56r2"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "9.4.0"
                }
              ]
            }
          ],
          "package": {
            "name": "generator-jhipster",
            "purl": "pkg:npm/generator-jhipster",
            "ecosystem": "npm"
          },
          "database_specific": {
            "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-9ffp-22j7-56r2/GHSA-9ffp-22j7-56r2.json"
          }
        },
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1.1.0"
                }
              ]
            }
          ],
          "package": {
            "name": "react-jhipster",
            "purl": "pkg:npm/react-jhipster",
            "ecosystem": "npm"
          },
          "database_specific": {
            "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-9ffp-22j7-56r2/GHSA-9ffp-22j7-56r2.json",
            "last_known_affected_version_range": "<= 1.0.3"
          }
        }
      ],
      "modified": "2026-10-08T18:00:09.700221111Z",
      "provider": "osv",
      "references": [
        "https://github.com/jhipster/generator-jhipster/security/advisories/GHSA-9ffp-22j7-56r2",
        "https://github.com/jhipster/generator-jhipster/pull/34807",
        "https://github.com/jhipster/generator-jhipster/commit/efe95edd4dedc3379735094936439410a51ce3d9",
        "https://github.com/jhipster/generator-jhipster",
        "https://github.com/jhipster/generator-jhipster/releases/tag/v9.4.0"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-79"
        ],
        "severity": "HIGH",
        "github_reviewed": true,
        "nvd_published_at": null,
        "github_reviewed_at": "2026-10-08T17:40:29Z"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-107303",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/database_specific/severity"
  },
  "source_id": "core-osv",
  "document_id": 104437,
  "published_at": "2026-10-08T17:40:29+00:00"
}