CVE-2023-40027 is a low-severity (CVSS 3.7) CWE-862 vulnerability in @keystone-6/core. A fix is available for @keystone-6/core — see the affected versions and patch details below.
Conditionally missing authorization in @keystone-6/core
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 CVE-2023-40027.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2023-40027 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,166 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
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.
@keystone-6/corenpmDescription
Keystone is an open source headless CMS for Node.js — built with GraphQL and React. When ui.isAccessAllowed is set as undefined, the adminMeta GraphQL query is publicly accessible (no session required). This is different to the behaviour of the default AdminUI middleware, which by default will only be publicly accessible (no session required) if a session strategy is not defined. This vulnerability does not affect developers using the @keystone-6/auth package, or any users that have written their own ui.isAccessAllowed (that is to say, isAccessAllowed is not undefined). This vulnerability does affect users who believed that their session strategy will, by default, enforce that adminMeta is inaccessible by the public in accordance with that strategy; akin to the behaviour of the AdminUI middleware. This vulnerability has been patched in @keystone-6/core version 5.5.1. Users are advised to upgrade. Users unable to upgrade may opt to write their own isAccessAllowed functionality to work-around this vulnerability.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @keystone-6/core | all versions | 5.5.1npm install @keystone-6/core@5.5.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @keystone-6/core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @keystone-6/core to 5.5.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-40027 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2023-40027 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-40027. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2023-40027 in your dependencies?
O3 Security finds CVE-2023-40027 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.