CVE-2023-40027: Keystone is an open source headless CMS for Node.js — built with GraphQL and React. When `ui.isAccessAllowed` is set as `undefined`, the `adminMeta` G...

Description

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.

Metrics

CVSS 3.1

5.3/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS Probability

0.47%

37.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-862

Affected Software

Vendor	Product	Versions
Keystonejs	Keystone	< 5.5.1

References

Timeline

Published: Aug 15, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-40027?

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.

How severe is CVE-2023-40027?

CVE-2023-40027 has a CVSS score of 5.3/10 (MEDIUM severity). The EPSS model estimates a 0.47% probability of exploitation in the next 30 days.

How do I fix CVE-2023-40027?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.