CVE-2026-45568

zrok is software for sharing web services, files, and network resources. Prior to 2.0.3, zrok's Python SDK ProxyShare Flask proxy route accepts an absolute URL in the request path and passes it to urllib.parse.urljoin, allowing the requested path to replace the configured target host and causing requests.request to return a server-side response from an attacker-chosen URL. This issue is fixed in version 2.0.3.

zrok is software for sharing web services, files, and network resources. Prior to 2.0.3, zrok's Python SDK ProxyShare Flask proxy route accepts an absolute URL in the request path and passes it to urllib.parse.urljoin, allowing the requested path to replace the configured target host and causing requests.request to return a server-side response from an attacker-chosen URL. This issue is fixed in version 2.0.3.

Summary

Alice exposes a Python SDK ProxyShare with a fixed target URL. Bob sends a request to the share with an absolute URL in the path. The Flask handler passes that path to urllib.parse.urljoin, which replaces Alice's configured target host with Bob's host and returns the server-side response to Bob.

Details

The Python SDK proxy route accepts every path under the share:

@app.route('/', defaults={'path': ''}, methods=['GET', 'POST', 'PUT', 'DELETE', 'PATCH', 'OPTIONS'])
@app.route('/<path:path>', methods=['GET', 'POST', 'PUT', 'DELETE', 'PATCH', 'OPTIONS'])
def proxy(path):

It constructs the outbound URL with urljoin and then sends the request:

url = urllib.parse.urljoin(self.target, path)
resp = requests.request(
    method=request.method,
    url=url,
    headers={key: value for (key, value) in request.headers
             if key.lower() not in HOP_BY_HOP_HEADERS},
    data=request.get_data(),
    cookies=request.cookies,
    allow_redirects=False,
    stream=True,
    verify=self.verify_ssl
)

When path is [http://127.0.0.1:19190/metadata](http://127.0.0.1:19190/metadata%60), urljoin(self.target, path) returns [http://127.0.0.1:19190/metadata](http://127.0.0.1:19190/metadata%60). The proxy sends the request to Bob's chosen URL rather than Alice's target.

zrok is software for sharing web services, files, and network resources. Prior to 2.0.3, zrok's Python SDK ProxyShare Flask proxy route accepts an absolute URL in the request path and passes it to urllib.parse.urljoin, allowing the requested path to replace the configured target host and causing requests.request to return a server-side response from an attacker-chosen URL. This issue is fixed in version 2.0.3.

zrok is software for sharing web services, files, and network resources. Prior to 2.0.3, zrok's Python SDK ProxyShare Flask proxy route accepts an absolute URL in the request path and passes it to urllib.parse.urljoin, allowing the requested path to replace the configured target host and causing requests.request to return a server-side response from an attacker-chosen URL. This issue is fixed in version 2.0.3.

Summary

Alice exposes a Python SDK ProxyShare with a fixed target URL. Bob sends a request to the share with an absolute URL in the path. The Flask handler passes that path to urllib.parse.urljoin, which replaces Alice's configured target host with Bob's host and returns the server-side response to Bob.

Details

The Python SDK proxy route accepts every path under the share:

@app.route('/', defaults={'path': ''}, methods=['GET', 'POST', 'PUT', 'DELETE', 'PATCH', 'OPTIONS'])
@app.route('/<path:path>', methods=['GET', 'POST', 'PUT', 'DELETE', 'PATCH', 'OPTIONS'])
def proxy(path):

It constructs the outbound URL with urljoin and then sends the request:

url = urllib.parse.urljoin(self.target, path)
resp = requests.request(
    method=request.method,
    url=url,
    headers={key: value for (key, value) in request.headers
             if key.lower() not in HOP_BY_HOP_HEADERS},
    data=request.get_data(),
    cookies=request.cookies,
    allow_redirects=False,
    stream=True,
    verify=self.verify_ssl
)

When path is [http://127.0.0.1:19190/metadata](http://127.0.0.1:19190/metadata%60), urljoin(self.target, path) returns [http://127.0.0.1:19190/metadata](http://127.0.0.1:19190/metadata%60). The proxy sends the request to Bob's chosen URL rather than Alice's target.

Summary

Alice exposes a Python SDK ProxyShare with a fixed target URL. Bob sends a request to the share with an absolute URL in the path. The Flask handler passes that path to urllib.parse.urljoin, which replaces Alice's configured target host with Bob's host and returns the server-side response to Bob.

Details

The Python SDK proxy route accepts every path under the share:

@app.route('/', defaults={'path': ''}, methods=['GET', 'POST', 'PUT', 'DELETE', 'PATCH', 'OPTIONS'])
@app.route('/<path:path>', methods=['GET', 'POST', 'PUT', 'DELETE', 'PATCH', 'OPTIONS'])
def proxy(path):

It constructs the outbound URL with urljoin and then sends the request:

url = urllib.parse.urljoin(self.target, path)
resp = requests.request(
    method=request.method,
    url=url,
    headers={key: value for (key, value) in request.headers
             if key.lower() not in HOP_BY_HOP_HEADERS},
    data=request.get_data(),
    cookies=request.cookies,
    allow_redirects=False,
    stream=True,
    verify=self.verify_ssl
)

When path is [http://127.0.0.1:19190/metadata](http://127.0.0.1:19190/metadata%60), urljoin(self.target, path) returns [http://127.0.0.1:19190/metadata](http://127.0.0.1:19190/metadata%60). The proxy sends the request to Bob's chosen URL rather than Alice's target.