{"id":"PYSEC-2026-3821","summary":"django CMS: Broken access control in page *Duplicate* allows reading the content of any page (cross-site / restriction bypass)","details":"## Impact\n\nThe only authorization gate on the duplicate flow is `PageAdmin.has_add_permission`,\nwhich checks `user_can_add_page(user, site)` / `user_can_add_subpage(...)` — i.e. *“may\nthis user create a page at all”*. Nothing checks the user’s relationship to the page being\ncopied:\n\n- `cms/admin/forms.py` — `DuplicatePageForm.source = ModelChoiceField(queryset=Page.objects.all(), widget=HiddenInput())`\n  spans **every page in the database, on every site**.\n- `cms/admin/forms.py` — `AddPageForm.__init__` returns early when the `source` widget is\n  hidden, so the queryset is **never narrowed** to the user’s site/subtree.\n- `cms/admin/forms.py` — `AddPageForm.clean()` validates only URL uniqueness; `source` is\n  never validated against the user.\n- `cms/admin/pageadmin.py` — `duplicate()` seeds `source` from the URL **only on GET**; on\n  POST the value comes entirely from the request body.\n- `cms/admin/forms.py` — `AddPageForm.save()` → `from_source()` performs\n  `source.copy(..., permissions=False)` and copies **every placeholder and all plugins** of\n  `source` into a new page on the attacker’s site. Because `permissions=False` drops the\n  source’s view restrictions, the resulting copy is fully readable by the attacker.\n\nThis crosses a real privilege boundary: a staff user restricted (via `CMS_PERMISSION`) to\ntheir own site or subtree can exfiltrate the content of restricted pages and of pages\nbelonging to other tenants.\n\n**Read-back is trivial (verified):** the copy is created on the attacker’s site and, because\n`copy(..., permissions=False)` strips the source’s view restrictions, the new page is\n*unrestricted*. `user_can_view_page()` then returns `True` for it (unrestricted +\n`PUBLIC_FOR`), so the attacker — or even an anonymous visitor — can read the duplicated\ncontent directly from the front end. No further permission on the new page is required.\n\n## Proof of concept\n\n1. Log in as a staff user `attacker` who has *add page* permission but **no** view/change\n   permission on a target (secret / other-site) page `SECRET_ID`.\n2. Send (the URL `\u003cid\u003e` only needs to be a `PageContent` the attacker can already see —\n   e.g. one of their own pages; the victim id goes in the POST body):\n\n```http\nPOST /admin/cms/pagecontent/\u003cMY_OWN_PAGECONTENT_ID\u003e/duplicate/ HTTP/1.1\nCookie: sessionid=\u003cattacker session\u003e\nContent-Type: application/x-www-form-urlencoded\n\ncsrfmiddlewaretoken=...&title=x&slug=x&language=en&source=\u003cSECRET_ID\u003e\n```\n\n3. A new, unrestricted page is created under the attacker’s site containing a verbatim\n   copy of the secret page’s plugins, which the attacker can now preview/edit/read.\n\n## Patches \n\nEnforce an object-level permission check on `source`:\n\n```python\nclass DuplicatePageForm(AddPageForm):\n    source = forms.ModelChoiceField(\n        queryset=Page.objects.all(),\n        required=True,\n        widget=forms.HiddenInput(),\n    )\n\n    def clean_source(self):\n        source = self.cleaned_data.get(\"source\")\n        if source and not user_can_view_page(self._user, source):\n            raise ValidationError(_(\"You do not have permission to copy this page.\"))\n        return source\n```\n\n(`user_can_view_page` is imported from `cms.utils.page_permissions`.)\n\n## Workarounds\n\nUntil patched, restrict access to the `cms.add_page` permission to fully-trusted staff, or\ndisable the duplicate action for delegated/limited editors.\n\n## References\n\n- `cms/admin/pageadmin.py` — `duplicate()`, `has_add_permission()`, `get_urls()`\n- `cms/admin/forms.py` — `DuplicatePageForm`, `AddPageForm.__init__/clean/save/from_source`\n- Regression tests: `cms/tests/test_forms.py::DuplicatePageFormSecurityTestCase`","aliases":["CVE-2026-63003","GHSA-6x92-6vx4-5fwr"],"modified":"2026-09-10T12:15:03.041235202Z","published":"2026-09-10T09:44:52.697049Z","references":[{"type":"WEB","url":"https://github.com/django-cms/django-cms/security/advisories/GHSA-6x92-6vx4-5fwr"},{"type":"WEB","url":"https://github.com/django-cms/django-cms/pull/8713"},{"type":"WEB","url":"https://github.com/django-cms/django-cms/commit/3e1ccf7573eb1a74ebbbfaaa812c1f5cadf14e6c"},{"type":"PACKAGE","url":"https://github.com/django-cms/django-cms"},{"type":"WEB","url":"https://github.com/django-cms/django-cms/releases/tag/5.0.9"},{"type":"PACKAGE","url":"https://pypi.org/project/django-cms"},{"type":"ADVISORY","url":"https://github.com/advisories/GHSA-6x92-6vx4-5fwr"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63003"}],"affected":[{"package":{"name":"django-cms","ecosystem":"PyPI","purl":"pkg:pypi/django-cms"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.0.9"}]}],"versions":["2.0.1","2.0.2","2.1.1","2.1.2","2.1.3","2.1.4","2.1.5","2.2","2.2.1","2.3.1","2.3.2","2.3.3","2.3.4","2.3.5","2.3.6","2.3.7","2.3.8","2.4.0","2.4.1","2.4.2","2.4.3","3.0","3.0.1","3.0.10","3.0.11","3.0.12","3.0.13","3.0.14","3.0.15","3.0.16","3.0.17","3.0.18","3.0.2","3.0.3","3.0.4","3.0.5","3.0.6","3.0.7","3.0.8","3.0.9","3.1.0","3.1.0.b1","3.1.0rc1","3.1.0rc2","3.1.1","3.1.2","3.1.3","3.1.4","3.1.5","3.1.6","3.1.7","3.10.0","3.10.0rc1","3.10.0rc2","3.10.1","3.10.1rc1","3.11.0","3.11.1","3.11.10","3.11.11","3.11.1rc1","3.11.2","3.11.3","3.11.4","3.11.5","3.11.6","3.11.7","3.11.8","3.11.9","3.2.0","3.2.1","3.2.2","3.2.3","3.2.4","3.2.5","3.3.0","3.3.0rc2","3.3.0rc3","3.3.0rc4","3.3.1","3.3.2","3.3.3","3.3.4","3.4.0","3.4.1","3.4.2","3.4.3","3.4.4","3.4.5","3.4.6","3.4.7","3.5.0","3.5.1","3.5.2","3.5.3","3.5.4","3.6.0","3.6.0rc1","3.6.0rc3","3.6.1","3.7.0","3.7.0rc1","3.7.0rc2","3.7.1","3.7.2","3.7.3","3.7.4","3.8.0","3.8.0rc1","3.8.1","3.8.2","3.9.0","3.9.0rc1","3.9.0rc2","3.9.0rc3","4.1.0","4.1.0rc1","4.1.0rc2","4.1.0rc3","4.1.0rc4","4.1.0rc5","4.1.1","4.1.10","4.1.11","4.1.2","4.1.3","4.1.4","4.1.5","4.1.6","4.1.7","4.1.9","5.0.0","5.0.0a1","5.0.1","5.0.2","5.0.3","5.0.4","5.0.5","5.0.6","5.0.7","5.0.8"],"database_specific":{"source":"https://github.com/pypa/advisory-database/blob/main/vulns/django-cms/PYSEC-2026-3821.yaml"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N"}]}