---
title: "CVE-2026-49257: mcp-pinot: Unauthenticated tool invocation via default oauth_enabled=False + host 0.0.0.0 bind"
url: https://erroneo.us/security/cve/CVE-2026-49257/
description: "CVE-2026-49257 (mcp-pinot-server (PyPI)): mcp-pinot is a Python-based Model Context Protocol (MCP) server for interacting with Apache Pinot. In versions…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-06-18
date_modified: 2026-06-26
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-49257"
kev: false
cvss: 10
epss: 0.0093
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-49257: mcp-pinot: Unauthenticated tool invocation via default oauth_enabled=False + host 0.0.0.0 bind

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.9% , percentile 60: FIRST’s model estimates a 0.9% chance of exploitation activity in the next 30 days, higher than 60% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes mcp-pinot-server (PyPI) <= 3.0.1, fixed in 3.1.0 . Check your lockfile, including transitive dependencies.

## What it is

mcp-pinot is a Python-based Model Context Protocol (MCP) server for interacting with Apache Pinot. In versions 3.0.1 and below, mcp-pinot defaults to running an HTTP MCP server bound to 0.0.0.0:8080 with no authentication enabled. All MCP tools, including SQL query execution, schema creation, and table-config mutation, are reachable by any network-adjacent caller. The server proxies these calls using server-side Pinot credentials, producing a confused-deputy condition that yields full read/write access to the configured Pinot cluster. This issue has been fixed in version 3.1.0

## Affected packages

- PyPI `mcp-pinot-server` <= 3.0.1 → fixed: 3.1.0

## Affected products (CVE record)

- startreedata mcp-pinot: < 3.1.0

## Severity

- GitHub_M CVSS 3.1: 10 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H`
- GitHub CVSS 3.1: 10.0 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.93% probability of exploitation activity in the next 30 days; percentile 60.

## Sources

- [GitHub Advisory GHSA-73cv-556c-w3g6](https://github.com/advisories/GHSA-73cv-556c-w3g6)
- [CVE.org record CVE-2026-49257](https://www.cve.org/CVERecord?id=CVE-2026-49257)
- [NVD entry CVE-2026-49257](https://nvd.nist.gov/vuln/detail/CVE-2026-49257)
- [github.com](https://github.com/startreedata/mcp-pinot/security/advisories/GHSA-73cv-556c-w3g6)
- [github.com](https://github.com/startreedata/mcp-pinot/issues/90)
- [github.com](https://github.com/startreedata/mcp-pinot/pull/95)
- [github.com](https://github.com/startreedata/mcp-pinot/commit/1c7d3f9cd384854bf72c127d230bdb32299475ad)

---
Source page: https://erroneo.us/security/cve/CVE-2026-49257/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt