Security Digest · Vulnerability record
CVE-2026-49257: mcp-pinot: Unauthenticated tool invocation via default oauth_enabled=False + host 0.0.0.0 bind
mcp-pinot is a Python-based Model Context Protocol (MCP) server for interacting with Apache Pinot.
CVSS 10.0 Critical EPSS 0.9% · p60
Should you act?
Critical and remotely reachable
No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- 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
From the GitHub advisory
Resolution
Fixed in v3.1.0, released 2026-05-25. The fix was merged in PR #95 at commit 1c7d3f9.
The fix changes the default HTTP bind host to 127.0.0.1, refuses non-loopback HTTP/HTTPS exposure unless OAuth is enabled, makes Helm exposure opt-in and OAuth-gated, and adds parser-backed single-statement read-only validation for read-query.
CVSS evaluation
Reviewed on 2026-05-25. The advisory remains Critical with CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H = 10.0.
Weakness type: CWE-306.
Product: mcp-pinot-server (PyPI) · Assigned by: GitHub_M · Published: 2026-06-18
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| PyPI | mcp-pinot-server | <= 3.0.1 | 3.1.0 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| startreedata | mcp-pinot | < 3.1.0 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_M | 3.1 | 10 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H |
| GitHub | 3.1 | 10.0 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: none
- Scope: changed (can affect other components)
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- 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.
Timeline
- — CVE record published by GitHub_M
- — CVE record last updated
- — GitHub-reviewed advisory GHSA-73cv-556c-w3g6 published (critical)
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-73cv-556c-w3g6 github.com
- CVE.org record CVE-2026-49257 cve.org
- NVD entry CVE-2026-49257 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com
- github.com github.com
- github.com github.com
- github.com github.com