CVE-2026-63421: keystonejs keystone Improper Input Validation
Vulnerability summary
CVE-2026-63421 is a high (CVSS 7.5) Improper Input Validation vulnerability in keystonejs keystone. EPSS estimates a 0.67% chance of exploitation in the next 30 days, higher than 51% of scored vulnerabilities.
Timeline
- 21-08-2026PublishedVulnerability first disclosed.
- 26-08-2026Last modifiedVulnerability information updated.
Description
Keystone is a content management system for Node.js. Prior to 6.5.3, the findMany resolver in packages/core/src/lib/core/queries/resolvers.ts compares the signed take argument directly with graphql.maxTake, allowing a remote unauthenticated GraphQL client to provide a negative take value whose magnitude exceeds the configured bound. The bypass also applies to relationship queries and can return more records than the developer intended, potentially exhausting service resources. This issue is fixed in version 6.5.3.
CVSS metrics
3 scores · 3 sources · 1 version- OSV · NpmEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- NVDNIST7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.67%
Chance of exploitation in the next 30 days
Percentile
51%
Versus all other CVEs
30-day change
+0.20 pp
From 0.47% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-20Improper Input ValidationThe product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
- CWE-480Use of Incorrect OperatorThe product accidentally uses the wrong operator, which changes the logic in security-relevant ways.
Affected systems
@keystone-61 product
- core< 6.5.3
Keystonejs1 product
- keystone< 6.5.3
2 vendors · 2 products