django CMS: Page cache ignores plugin-declared Vary headers (disclosure & poisoning)
Summary
The 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.
Details
_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.
Impact
- 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. - 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.
Applies only when CMS_PAGE_CACHE is enabled and at least one plugin implements get_vary_cache_on().
Patches
Fixed in 5.0.8: the page cache now folds the request's values implements get_vary_cache_on().
Patches
Fixed 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.
Workarounds
Disable CMS_PAGE_CACHE, or avoid plugins that rely on get_vary_cache_on(), until upgraded.
Credits
Reported by the security team at the University of Sydney ([@reporter]).
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | django-cms | < 5.0.8 | 5.0.8 |
References
- https://github.com/django-cms/django-cms/security/advisories/GHSA-fwjf-m4qw-9f2x
- https://nvd.nist.gov/vuln/detail/CVE-2026-54625
- https://github.com/django-cms/django-cms/pull/8646
- https://github.com/django-cms/django-cms/pull/8647
- https://github.com/django-cms/django-cms/commit/8758714b865ffa79c6bcd0e5c503958ea48885aa
- https://github.com/django-cms/django-cms/commit/d5dc1efa18d157445491c4b12c2dd1efd56f439f
- https://github.com/django-cms/django-cms
- https://github.com/django-cms/django-cms/releases/tag/5.0.8
- https://github.com/django-cms/django-cms/releases/tag/5.1.0
- https://pypi.org/project/django-cms
- https://github.com/advisories/GHSA-fwjf-m4qw-9f2x
- CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N- Weakness (CWE)
CWE-349, CWE-524- Platform
- Python (PyPI)
- Package
django-cms- Disclosed
- 24.08.2026
- Updated
- 11.10.2026 15:18
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-3824 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-fwjf-m4qw-9f2x - CC BY 4.0
Vulnerability history: django-cms
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
- 10
- First → latest
- 08.2017 08.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 2
- Medium 8
Disclosures per year
- 2017: 1
- 2018: 0
- 2019: 0
- 2020: 0
- 2021: 0
- 2022: 1
- 2023: 0
- 2024: 1
- 2025: 0
- 2026: 7
-
django CMS: Page cache ignores plugin-declared Vary headers (disclosure & poisoning) this entry
Know which vulnerabilities affect your application
With the DockRay integration and software inventory enabled, DockRay checks reported component versions against known vulnerabilities and notifies you about confirmed matches. Coverage depends on the supported technology and available advisory data.