{"id":"PYSEC-2026-3824","summary":"django CMS: Page cache ignores plugin-declared Vary headers (disclosure & poisoning)","details":"### Summary\nThe CMS page cache key ignores the request headers that plugins declare via `get_vary_cache_on()`. The header is added to the response `Vary` header, but the CMS's own cache key does not incorporate the header values, so the first visitor's variant is served to all subsequent visitors regardless of their header values.\n\n### Details\n`_page_cache_key` (in `cms/cache/page.py`) keys only on cache prefix, site, language, path and timezone. `set_page_cache` collects the plugin-declared vary headers and calls `patch_vary_headers(response, ...)` (affecting only the emitted `Vary` header), but stores and retrieves the cached page under the header-agnostic key. `get_page_cache` therefore returns whichever variant was cached first.\n\n### Impact\n- **Information disclosure:** when a plugin varies its output on a request  header (e.g. `Country-Code`), the variant rendered for the first anonymous visitor is served to everyone until the entry expires, leaking request-specific content across users.\n- **Cache poisoning:** an unauthenticated attacker can prime the anonymous page cache with content rendered from attacker-chosen header values, which is then served to subsequent visitors.\n\nApplies only when `CMS_PAGE_CACHE` is enabled and at least one plugin implements `get_vary_cache_on()`.\n\n### Patches\nFixed in 5.0.8: the page cache now folds the request's values implements `get_vary_cache_on()`.\n\n### Patches\nFixed in 5.0.8: the page cache now folds the request's values for plugin-declared vary headers into the content key. The set of vary headers is persisted on write and looked up first on read (mirroring Django's  `learn_cache_key`/`get_cache_key`); a missing header-list entry degrades to a cache miss, never a wrong-variant hit.\n\n### Workarounds\nDisable `CMS_PAGE_CACHE`, or avoid plugins that rely on `get_vary_cache_on()`, until upgraded.\n\n### Credits\nReported by the security team at the University of Sydney ([@reporter]).","aliases":["CVE-2026-54625","GHSA-fwjf-m4qw-9f2x"],"modified":"2026-09-10T12:15:05.544597177Z","published":"2026-09-10T09:44:53.378969Z","references":[{"type":"WEB","url":"https://github.com/django-cms/django-cms/security/advisories/GHSA-fwjf-m4qw-9f2x"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-54625"},{"type":"WEB","url":"https://github.com/django-cms/django-cms/pull/8646"},{"type":"WEB","url":"https://github.com/django-cms/django-cms/pull/8647"},{"type":"WEB","url":"https://github.com/django-cms/django-cms/commit/8758714b865ffa79c6bcd0e5c503958ea48885aa"},{"type":"WEB","url":"https://github.com/django-cms/django-cms/commit/d5dc1efa18d157445491c4b12c2dd1efd56f439f"},{"type":"PACKAGE","url":"https://github.com/django-cms/django-cms"},{"type":"WEB","url":"https://github.com/django-cms/django-cms/releases/tag/5.0.8"},{"type":"WEB","url":"https://github.com/django-cms/django-cms/releases/tag/5.1.0"},{"type":"PACKAGE","url":"https://pypi.org/project/django-cms"},{"type":"ADVISORY","url":"https://github.com/advisories/GHSA-fwjf-m4qw-9f2x"}],"affected":[{"package":{"name":"django-cms","ecosystem":"PyPI","purl":"pkg:pypi/django-cms"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.0.8"}]}],"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"],"database_specific":{"source":"https://github.com/pypa/advisory-database/blob/main/vulns/django-cms/PYSEC-2026-3824.yaml"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N"}]}