Budibase: Unauthenticated S3 signed upload URL generation allows arbitrary writes with stored datasource credentials

Exploitation

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

CVSS

7.4 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L

EPSS

• CVE-2026-50136: 0.29% estimated exploitation activity in the next 30 days; percentile 21.66 (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.

The application server exposes an unauthenticated endpoint that generates S3 PutObject presigned URLs using credentials stored in a workspace datasource. The route is protected only by the recaptcha middleware and does not require authentication, table permission, datasource permission, or builder access. A public caller who knows a workspace ID and S3 datasource ID can request a signed upload URL for attacker-controlled bucket and key values. Details The static route registers the signed upload URL endpoint with only recaptcha before the controller: - packages/server/src/api/routes/static.ts:44-48 The controller loads the datasource by datasourceId with enriched secret values: - packages/server/src/api/controllers/static/index.ts:590-598 The request body controls bucket and key, and the server signs a PUT URL using the stored datasource credentials: - packages/server/src/api/controllers/static/index.ts:609-629 The endpoint returns the signed URL and public URL to the caller: -…

Published by the source

22 Jun 2026, 23:15 UTC

Last modified by the source

17 Jul 2026, 17:15 UTC

Source last checked

26 Oct 2026, 12:57 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-jj36-r9w3-3pfh

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-jj36-r9w3-3pfh

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# Patch Next advisory brief: CVE-2026-50136

Advisory: Budibase: Unauthenticated S3 signed upload URL generation allows arbitrary writes with stored datasource credentials
IDs: CVE-2026-50136, GHSA-jj36-r9w3-3pfh
Record: https://patchnext.com/advisories/cve-2026-50136 (revision 2, source checked 26 Oct 2026, 12:57 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.4)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: @budibase/server 3.39.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @budibase/server: affected < 3.39.2; fixed in 3.39.2

## Suggested inspection (read-only)
- `npm ls @budibase/server --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 @budibase/server.
- 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://osv.dev/vulnerability/GHSA-jj36-r9w3-3pfh (OSV record GHSA-jj36-r9w3-3pfh lists affected ranges: npm @budibase/server >=0 <3.39.2 (fixed))
- Verified: https://github.com/advisories/GHSA-jj36-r9w3-3pfh (GitHub-reviewed advisory GHSA-jj36-r9w3-3pfh lists affected ranges: npm @budibase/server >=0 <3.39.2)

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