CVE-2026-63421: CWE-20: Improper Input Validation in keystonejs keystone
Description
CVE-2026-63421 is an improper input validation vulnerability in KeystoneJS prior to version 6.5.3. It allows a remote unauthenticated GraphQL client to provide a negative 'take' argument with a magnitude exceeding the configured maximum, bypassing intended query limits. This can lead to returning more records than intended, potentially exhausting service resources. The issue affects the findMany resolver and relationship queries. The vulnerability is fixed in KeystoneJS version 6.5.3.
CVSS v3.1
Score 7.5high
Affected software
keystonejs
keystone
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
KeystoneJS, a Node.js content management system, has an input validation flaw in the findMany resolver within packages/core/src/lib/core/queries/resolvers.ts. Before version 6.5.3, the resolver compares the signed 'take' argument directly with the configured 'graphql.maxTake' limit without properly validating negative values. This allows an unauthenticated remote GraphQL client to submit a negative 'take' value whose absolute value exceeds the maximum, effectively bypassing the limit and returning more records than intended. This bypass also applies to relationship queries, which can lead to resource exhaustion on the service. The vulnerability is addressed in version 6.5.3.
Potential Impact
An unauthenticated remote attacker can exploit this vulnerability to bypass query limits and retrieve more records than intended by the developer. This can lead to resource exhaustion on the affected KeystoneJS service, potentially causing denial of service conditions. There is no direct impact on confidentiality or integrity reported.
Mitigation Recommendations
Upgrade KeystoneJS to version 6.5.3 or later, where this vulnerability is fixed. No other mitigations are specified. Patch status is confirmed as an official fix in version 6.5.3.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-07-16T19:20:28.988Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6a88b3a2acd9273b49af19fa
Added to database: 08/21/2026, 20:22:58 UTC
Last enriched: 09/10/2026, 17:06:46 UTC
Last updated: 10/05/2026, 18:48:21 UTC
Views: 80
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