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TI-2026-12269 Aliases CVE-2026-14539GHSA-623p-8r6m-hwc6

Denial of Service via Unrestricted Payload Buffering in MCP Toolbox

Priority LOW 35CWE-770Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-770.

Summary

An allocation of resources without limits vulnerability in the HTTP handler component of Google mcp-toolbox versions up to and including 1.4.0 allows an unauthenticated attacker to cause a denial of service (DoS). The /mcp endpoint handler reads incoming payloads directly into system memory using an unrestricted buffer loop (io.ReadAll) without applying defensive constraints such as http.MaxBytesReader or pre-read Content-Length enforcement. By submitting a single, massive HTTP request body, an attacker can linearly consume available host memory until the runtime process is terminated by an Out-Of-Memory (OOM) error.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00238 14th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Googlemcp-toolbox0.0.0 – 1.4.0—No fix listedCNA
  • mcp-toolbox VendorGoogle Affected 0.0.0 – 1.4.0 Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:google:mcp_toolbox_for_databases:*:*:*:*:*:*:*:*before 1.5.0VulnerableGoogle
  • cpe:2.3:a:google:mcp_toolbox_for_databases:*:*:*:*:*:*:*:* Versions before 1.5.0 Vulnerable ·Google

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-14539
  2. 2026-10-03 Alias added: GHSA-623p-8r6m-hwc6

References

Patch 1

  • TI-2026-10124 Path Traversal in googleapis/mcp-toolbox HTTP Tool URL Builder CVSS 4.0CRITICAL 9.3
  • TI-2026-10122 Improper authentication in Google MCP Toolbox for Databases CVSS 4.0CRITICAL 9.3
  • TI-2026-10121 Improper authentication in Google MCP Toolbox for Databases CVSS 4.0CRITICAL 9.3
  • TI-2026-12267 Authorization Bypass in MCP Toolbox Legacy HTTP Endpoints CVSS 4.0HIGH 8.1
  • TI-2026-12271 Authentication Bypass and Audience Confusion in MCP Toolbox OAuth Provider CVSS 4.0HIGH 8.0
  • TI-2026-12270 Server-Side Request Forgery via Unrestricted HTTP Redirection in MCP Toolbox CVSS 4.0HIGH 8.0
See all 10 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences