Summary
django CMS: Page cache ignores plugin-declared Vary headers (disclosure & poisoning)
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.
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]).
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().
CVE-2026-54625 has a CVSS score of 4.8 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (5.0.8); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Fixed in 5.0.8: the page cache now folds the request's values implements get_vary_cache_on().
Frequently Asked Questions
- What is CVE-2026-54625? CVE-2026-54625 is a medium-severity security vulnerability in django-cms (pip), affecting versions < 5.0.8. It is fixed in 5.0.8.
- How severe is CVE-2026-54625? CVE-2026-54625 has a CVSS score of 4.8 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of django-cms are affected by CVE-2026-54625? django-cms (pip) versions < 5.0.8 is affected.
- Is there a fix for CVE-2026-54625? Yes. CVE-2026-54625 is fixed in 5.0.8. Upgrade to this version or later.
- Is CVE-2026-54625 exploitable, and should I be worried? Whether CVE-2026-54625 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-54625 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-54625? Upgrade
django-cmsto 5.0.8 or later.