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

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.6 · CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N

EPSS

• CVE-2026-107303: 0.32% estimated exploitation activity in the next 30 days; percentile 25.46 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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…

Published by the source

8 Oct 2026, 17:40 UTC

Last modified by the source

8 Oct 2026, 18:00 UTC

Source last checked

26 Oct 2026, 13:07 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-9ffp-22j7-56r2

2. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GHSA-9ffp-22j7-56r2

3. Revision 1 · created · 23 Oct 2026

   Published from ghsa record GHSA-9ffp-22j7-56r2

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# Patch Next advisory brief: CVE-2026-107303

Advisory: JHipster: Generated Applications Allow Stored XSS via Unrestricted Blob ContentType Opened as Same-Origin Blob
IDs: CVE-2026-107303, GHSA-9ffp-22j7-56r2
Record: https://patchnext.com/advisories/cve-2026-107303 (revision 3, source checked 26 Oct 2026, 13:07 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.6)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: generator-jhipster 9.4.0; react-jhipster 1.1.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm generator-jhipster: affected < 9.4.0; fixed in 9.4.0
- npm react-jhipster: affected <= 1.0.3; fixed in 1.1.0

## Suggested inspection (read-only)
- `npm ls generator-jhipster --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.
- `npm ls react-jhipster --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on generator-jhipster, react-jhipster.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-9ffp-22j7-56r2 (GitHub-reviewed advisory GHSA-9ffp-22j7-56r2 lists affected ranges: npm generator-jhipster >=0 =0 <=1.0.3)
- Verified: https://osv.dev/vulnerability/GHSA-9ffp-22j7-56r2 (OSV record GHSA-9ffp-22j7-56r2 lists affected ranges: npm generator-jhipster >=0 =0 <1.1.0 (fixed))

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