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PatchSiren cyber security CVE debrief

CVE-2026-49257 startreedata CVE debrief

A critical vulnerability was discovered in mcp-pinot, a Python-based Model Context Protocol (MCP) server for interacting with Apache Pinot. The vulnerability allows for full read/write access to the configured Pinot cluster due to a confused-deputy condition. This condition arises because mcp-pinot defaults to running an HTTP MCP server bound to 0.0.0.0:8080 with no authentication enabled, allowing all MCP tools, including SQL query execution, schema creation, and table-config mutation, to be reachable by any network-adjacent caller. The server proxies these calls using server-side Pinot credentials, producing the confused-deputy condition that yields full read/write access to the configured Pinot cluster.

Vendor
startreedata
Product
mcp-pinot
CVSS
CRITICAL 10
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-18
Original CVE updated
2026-06-23
Advisory published
2026-06-18
Advisory updated
2026-06-23

Who should care

Users of mcp-pinot versions 3.0.1 and below should apply the patch to prevent exploitation. This includes operators of Apache Pinot clusters who use mcp-pinot for interactions with the cluster, as well as security teams and vulnerability management teams responsible for ensuring the security of these systems.

Technical summary

mcp-pinot defaults to running an HTTP MCP server bound to 0.0.0.0:8080 with no authentication enabled, allowing all MCP tools, including SQL query execution, schema creation, and table-config mutation, to be 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.

Defensive priority

High

Recommended defensive actions

  • Apply the patch to upgrade to version 3.1.0
  • Disable the HTTP MCP server or restrict access to it
  • Monitor for suspicious activity on the Pinot cluster
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record was published on 2026-06-18T21:16:29.780Z and has been modified since then. The NVD entry is currently Deferred. Evidence is limited to public sources and may not reflect the full scope or impact of the vulnerability. Defenders should verify affected systems and apply patches or mitigations as needed.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-49257 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-49257

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-49257 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-49257

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.