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GHSA-9jj8-v89v-xjvw

MediumCVSS 5.3 / 10
Published Jul 20, 2026·Last modified Jul 20, 2026
Affected Components(0)

No affected components available

Description

Summary

The /static/<group>/<filename> route accepts group="..", which causes send_from_directory("static/..", filename) to execute. This moves the base directory up to /app/changedetectionio, enabling unauthenticated local file read of application source files (e.g., flask_app.py). Severity is low information disclosure (C:L).

Details

The vulnerable code is in changedetectionio/flask_app.py inside static_content():

group = re.sub(r'[^\w.-]+', '', group.lower())
filename = re.sub(r'[^\w.-]+', '', filename.lower())
...
return send_from_directory(f"static/{group}", path=filename)

The group sanitization allows dots, so group=".." passes validation.
This results in send_from_directory("static/..", filename), effectively shifting the base directory to /app/changedetectionio and allowing reads of files in that directory.
The route is unauthenticated, so any user can retrieve source files without logging in.

Limitation: the route only matches /static/<group>/<filename> and rejects slashes inside filename, so it cannot traverse further to arbitrary system paths like /etc/passwd. It is limited to files inside the application package directory.

PoC

  1. Start an instance (example: Docker on port 5050)
docker run -d --name cdio -p 127.0.0.1:5050:5000 -v cdio-data:/datastore cdio-local
  1. Reproduce
    (URL-encoded traversal)
curl -i http://127.0.0.1:5050/static/%2e%2e/flask_app.py

(curl path passthrough)

curl --path-as-is -i http://127.0.0.1:5050/static/../flask_app.py
  1. Observe that the response body contains Python source code from flask_app.py.

Impact

  • Vulnerability type: Directory Traversal / Local File Read
  • Affected users: Anyone with network access (no authentication required)
  • Scope: Source files under /app/changedetectionio
  • Security impact: Internal logic exposure can aid further exploitation (Confidentiality: Low)
Risk Scores
Base Score
5.3

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. The impact is confined to the system where the vulnerability exists. There is a low impact on the confidentiality of the information.

Threat Intelligence
4.9

Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.

EPSS
0.92%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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