dbt MCP Server: Unauthenticated OAuth Context Endpoint Leaks dbt Platform Tokens

Exploitation

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

CVSS

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

EPSS

• CVE-2026-55837: 0.27% estimated exploitation activity in the next 30 days; percentile 19.72 (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.

Unauthenticated OAuth Context Endpoint Leaks dbt Platform Tokens Summary The local OAuth helper FastAPI server bundled with dbt-mcp exposes the GET /dbtplatformcontext endpoint without any form of authentication or host-origin validation. After a user completes the OAuth login flow against dbt Cloud (cloud.getdbt.com), the endpoint returns the full DbtPlatformContext object — including the victim's accesstoken and refreshtoken for the dbt Platform API — verbatim to any caller that can reach 127.0.0.1:6785. An attacker who can direct the victim's browser to the helper origin via DNS rebinding, or who has co-located process access on the same host, can silently exfiltrate both tokens. The stolen bearer token grants full dbt Cloud API access as the victim; the refresh token enables persistent access beyond the original token's expiry. CVSS Base Score: 8.0 (High). Details During the OAuth login flow, dbt-mcp launches an embedded FastAPI server (the "OAuth helper") bound to 127.0.0.1…

Published by the source

19 Jun 2026, 21:15 UTC

Last modified by the source

13 Jul 2026, 16:42 UTC

Source last checked

26 Oct 2026, 13:46 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-jr33-mw75-7j8f

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-jr33-mw75-7j8f

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# Patch Next advisory brief: CVE-2026-55837

Advisory: dbt MCP Server: Unauthenticated OAuth Context Endpoint Leaks dbt Platform Tokens
IDs: CVE-2026-55837, GHSA-jr33-mw75-7j8f
Record: https://patchnext.com/advisories/cve-2026-55837 (revision 2, source checked 26 Oct 2026, 13:46 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: dbt-mcp 1.20.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI dbt-mcp: affected < 1.20.0; fixed in 1.20.0

## Suggested inspection (read-only)
- `python -m pip show dbt-mcp`: prints the installed version. Run with the environment that serves production active.

## 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 dbt-mcp.
- 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-jr33-mw75-7j8f (OSV record GHSA-jr33-mw75-7j8f lists affected ranges: PyPI dbt-mcp >=0 <1.20.0 (fixed))
- Verified: https://github.com/advisories/GHSA-jr33-mw75-7j8f (GitHub-reviewed advisory GHSA-jr33-mw75-7j8f lists affected ranges: PyPI dbt-mcp >=0 <1.20.0)

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