---
cve: "CVE-2026-67531"
severity: "CRITICAL"
cvss: 9.3
epss: "0.6%"
vendor: "agentfront"
kev: false
exploited: false
published: "2026-08-05 22:54:36"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-09-21T18:27:06+02:00"
---

# CVE-2026-67531

> 9.3 CRITICAL · 🧪 PoC

## Beschreibung

FrontMCP is a TypeScript-first framework for the Model Context Protocol (MCP). Prior to 1.5.7, the sandboxed codecall:execute tool exposes live host Zod schema instances to the script via getTool(), and because Zod v4 defines _zod as a non-configurable, non-writable own property, the ECMAScript Proxy invariants force the security membrane to hand back the raw host object, letting a script reach _zod.constr.constructor (the host Function constructor) and execute arbitrary code in the server process. A single tools/call is sufficient to escape the sandbox and achieve remote code execution as the server user, exposing everything the process holds such as OAuth client secrets, JWT_SECRET, session keys, database credentials, and cloud instance metadata. Because the framework's DEFAULT_AUTH_OPTIONS is public mode, an unconfigured server serves this to unauthenticated callers, and on authenticated servers an indirect prompt injection in tool output or fetched content can trigger it without a human attackerThis issue is fixed in version 1.5.7.

## CVSS-Vektor

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

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

## Patch verfügbar (OSV)

- 209cddd19a8d4db0777f725b527818da7df6f67f (Commit)

## Referenzen

- <https://github.com/agentfront/frontmcp/security/advisories/GHSA-mp29-fxh8-92px>
- <https://github.com/agentfront/frontmcp/commit/209cddd19a8d4db0777f725b527818da7df6f67f>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-67531) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_