ApostropheCMS: POST /api/v1/@apostrophecms/doc/slugTaken discloses existence of private/admin-only content to any authenticated userGHSA-f66c-mpj2-3r8h
MEDIUMFix: apostrophecms/apostrophe@06e4b37GHSA-f66c-mpj2-3r8h is a medium-severity (CVSS 4.3) Information Exposure vulnerability in apostrophe. A fix is available for apostrophe — see the affected versions and patch details below.
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-f66c-mpj2-3r8h.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
GHSA-f66c-mpj2-3r8h by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 394,803 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
apostrophenpmDescription
Summary
The slugTaken endpoint returns a boolean indicating whether a slug is in use across
all document types and visibility levels, with no permission or type filter. Any logged-in
user (including editors) can enumerate the slug space of private pages, drafts, and
archived content.
Details
POST /api/v1/@apostrophecms/doc/slugTaken with body { "slug": "target-slug" } runs
a raw existence check against the documents collection. It does not:
- Check whether the requesting user has read permission for documents of that type.
- Filter by
visibility(public, loginRequired, private). - Filter by
viewRole. - Filter by publication status (draft vs published).
A single authenticated session can iterate the slug space to enumerate the full content inventory of the CMS, including content the user is explicitly prohibited from viewing.
PoC
# Any authenticated session works — editor role sufficient
curl -b "$EDITOR_JAR" -X POST \
-H "Content-Type: application/json" \
-d '{"slug":"known-private-page-slug"}' \
"http://TARGET/api/v1/@apostrophecms/doc/slugTaken"
# → { "taken": true } — confirms private page exists
curl -b "$EDITOR_JAR" -X POST \
-H "Content-Type: application/json" \
-d '{"slug":"zzz-nonexistent"}' \
"http://TARGET/api/v1/@apostrophecms/doc/slugTaken"
# → { "taken": false }
Impact
Information disclosure. An attacker with any authenticated session can enumerate all slugs in the system, mapping the full content structure of the CMS including private and admin-only content.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | apostrophe | all versions | 4.34.0npm install apostrophe@4.34.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for apostrophe, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update apostrophe to 4.34.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-f66c-mpj2-3r8h is resolved across your whole dependency graph.
Workarounds
Assume what was exposed is already known: rotate any credential, token or key that the affected component could return, restrict the endpoint to callers that genuinely need it, and strip sensitive fields from responses and error output at the boundary rather than relying on the client not to read them.
Frequently Asked Questions
Is GHSA-f66c-mpj2-3r8h in your dependencies?
Find it across npm, including transitive dependencies.