---
cve: "CVE-2026-14539"
severity: "MEDIUM"
cvss: 6.6
epss: "0.2%"
vendor: "Google"
kev: false
exploited: false
published: "2026-07-31 02:16:28"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-11-08T21:17:50+01:00"
---

# CVE-2026-14539

> 6.6 MEDIUM · 🧪 PoC

## Beschreibung

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.

## CNA-Record (Kanon, cvelistV5)

- CNA: **Google**
- State: PUBLISHED
- Stand: 2026-07-31 16:11:48
- CNA-CVSS: **6.6** (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U`)

## CISA-Anreicherung (vulnrichment/ADP)

- CISA-SSVC (Coordinator, v2.0.3):
  - Exploitation: **none**
  - Automatable: **yes**
  - Technical Impact: **partial**

## CVSS-Vektor

```
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |

## Schwachstellen-Klasse

- **CWE-770** — Allocation of Resources Without Limits or Throttling
  The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.

## Angriffsmuster (CAPEC)

- [CAPEC-125 — Flooding](https://capec.mitre.org/data/definitions/125.html) _(Severity: Medium)_
- [CAPEC-130 — Excessive Allocation](https://capec.mitre.org/data/definitions/130.html) _(Severity: Medium)_
- [CAPEC-147 — XML Ping of the Death](https://capec.mitre.org/data/definitions/147.html) _(Severity: Medium)_
- [CAPEC-197 — Exponential Data Expansion](https://capec.mitre.org/data/definitions/197.html) _(Severity: Medium)_
- [CAPEC-229 — Serialized Data Parameter Blowup](https://capec.mitre.org/data/definitions/229.html) _(Severity: High)_
- [CAPEC-230 — Serialized Data with Nested Payloads](https://capec.mitre.org/data/definitions/230.html) _(Severity: High)_
- [CAPEC-231 — Oversized Serialized Data Payloads](https://capec.mitre.org/data/definitions/231.html) _(Severity: High)_
- [CAPEC-469 — HTTP DoS](https://capec.mitre.org/data/definitions/469.html) _(Severity: Low)_

## ATT&CK-Techniken

- [T1498.001 — Network Denial of Service: Direct Network Flood](https://attack.mitre.org/techniques/T1498/001/)
- [T1499 — Endpoint Denial of Service](https://attack.mitre.org/techniques/T1499/)
- [T1499.003 — Endpoint Denial of Service:Application Exhaustion Flood](https://attack.mitre.org/techniques/T1499/003/)
- [T1499.002 — Endpoint Denial of Service: Service Exhaustion Flood](https://attack.mitre.org/techniques/T1499/002/)

## Patch verfügbar (OSV)

- 45c0f86ce0199a8aed9c980370dd2c03f2684f5a (Commit)

## Referenzen

- <https://github.com/googleapis/mcp-toolbox/pull/3216>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/sicherheitsluecken/cve-2026-14539/) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_