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PYSEC-2026-577
No affected components available
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.
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability.
Active exploitation in the wild has been confirmed. Immediate patching or mitigation is required.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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