Budibase: SSRF via OAuth2 token endpoint URL reaches internal hosts and cloud metadata

Exploitation

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

CVSS

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

EPSS

• CVE-2026-48153: 0.18% estimated exploitation activity in the next 30 days; percentile 6.97 (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 fetchToken in the OAuth2 SDK makes a POST to a builder-supplied URL with plain node-fetch, skipping the blacklist.isBlacklisted check that every other outbound fetch path in the codebase uses. The Joi schema for the OAuth2 URL has no scheme or host restriction. Alice, a builder, points an OAuth2 config at http://169.254.169.254/... or http://127.0.0.1:5984/; the server connects and returns response-body fragments in the validation result. Details packages/server/src/sdk/workspace/oauth2/utils.ts:17-65 defines fetchToken. Near the end: config.url is whatever the builder stored. fetchConfig has redirect: "follow" (the default), so a public URL that returns 302 to an internal target is also reachable. The route validation at packages/server/src/api/routes/oauth2.ts:9 accepts any string: The controller passes the URL into fetchToken through crud.ts. The /api/oauth2/validate endpoint (builder role) is the most direct attack path: it lives on builderRoutes, takes the URL from the…

Published by the source

22 Jun 2026, 22:45 UTC

Last modified by the source

10 Sep 2026, 03:50 UTC

Source last checked

26 Oct 2026, 12:56 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-4q6h-8p4v-67vq

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-4q6h-8p4v-67vq

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# Patch Next advisory brief: CVE-2026-48153

Advisory: Budibase: SSRF via OAuth2 token endpoint URL reaches internal hosts and cloud metadata
IDs: CVE-2026-48153, GHSA-4q6h-8p4v-67vq
Record: https://patchnext.com/advisories/cve-2026-48153 (revision 2, source checked 26 Oct 2026, 12:56 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: @budibase/server 3.39.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @budibase/server: affected < 3.39.0; fixed in 3.39.0

## 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-4q6h-8p4v-67vq (OSV record GHSA-4q6h-8p4v-67vq lists affected ranges: npm @budibase/server >=0 <3.39.0 (fixed))
- Verified: https://github.com/advisories/GHSA-4q6h-8p4v-67vq (GitHub-reviewed advisory GHSA-4q6h-8p4v-67vq lists affected ranges: npm @budibase/server >=0 <3.39.0)

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