CVE-2026-49257 Sumo Logic CSE · Sumo

Detect CVE-2026-49257: mcp-pinot Unauthenticated Tool Invocation via Default oauth_enabled=False in Sumo Logic CSE

Detects exploitation of CVE-2026-49257, a critical authentication bypass in mcp-pinot-server (<=3.0.1). The server defaults to oauth_enabled=False and binds to 0.0.0.0, allowing any network-adjacent or internet-facing attacker to invoke MCP tools without authentication. CVSS 10.0 with public PoC available.

MITRE ATT&CK

Tactic
Initial Access Privilege Escalation Exfiltration

Sumo Detection Query

Sumo Logic CSE (Sumo)
sql 
_sourceCategory=*web*access* OR _sourceCategory=*application*log* OR _sourceCategory=*python*
| where _raw matches /(?i)(mcp.?pinot|mcp_pinot|\/tools\/|\/invoke|\/call)/
| parse regex "\"(?P<method>POST|GET|PUT|DELETE) (?P<path>/[^\" ]+)" nodrop
| parse regex "Authorization:\s*(?P<auth_header>[^\r\n]+)" nodrop
| where method = "POST"
| where isNull(auth_header) or auth_header = ""
| where path matches /\/tools\/|\/invoke|\/call/
| count as unauthenticated_requests by _sourceHost, path, _sourceip
| sort by unauthenticated_requests desc
critical severity medium confidence

Sumo Logic query correlating HTTP POST requests to mcp-pinot tool endpoints lacking Authorization headers, surfacing hosts with unauthenticated invocation patterns consistent with CVE-2026-49257 exploitation.

Data Sources

Web access logsApplication logsPython runtime logs

Required Tables

_sourceCategory=*web*access*_sourceCategory=*application*log*

False Positives & Tuning

  • Service mesh environments using mutual TLS instead of bearer tokens
  • Internal automated test jobs without auth header configuration
  • Log sources where Authorization header is redacted before ingestion
  • Health monitoring systems polling the server without credentials

Other platforms for CVE-2026-49257

Microsoft Sentinel (KQL) Splunk (SPL) Elastic Security (Elastic) IBM QRadar (QRadar) Google Chronicle (YARA-L) CrowdStrike LogScale (LogScale) All platforms (combined) →

Testing Methodology

Validate this detection against 4 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.

  1. Test 1Verify Unauthenticated MCP Tool Listing

    Expected signal: HTTP 200 response with JSON list of available Pinot MCP tools returned without any authentication challenge; no 401 or 403 status code issued.

  2. Test 2Unauthenticated Pinot Query Execution via MCP Tool

    Expected signal: Pinot query execution log entry showing query 'SELECT * FROM myTable LIMIT 10' from MCP server without session token; HTTP 200 from mcp-pinot-server with query results in response body.

  3. Test 3External Network Exploitation Simulation

    Expected signal: Inbound TCP connection from external IP to port 8000; HTTP POST to /tools/list and /tools/call with source IP from outside trusted ranges; no TLS client certificate or Authorization header present.

  4. Test 4Confirm Vulnerable Package Version in Environment

    Expected signal: Command execution events showing pip, find, and ps commands with mcp-pinot arguments; output revealing package version <= 3.0.1 and running process details.

Last updated: 2026-06-27 Research depth: standard
References (6)

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TA0001Initial AccessTA0004Privilege EscalationTA0010Exfiltration

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