CVE-2026-23897

Apollo Server is vulnerable to denial of service with `startStandaloneServer`

State: Published
Severity: 7.5 High
Published: Feb 4, 2026
Updated: Feb 4, 2026
Reserved: Jan 16, 2026

Description

Apollo Server is an open-source, spec-compliant GraphQL server that's compatible with any GraphQL client, including Apollo Client. In versions from 2.0.0 to 3.13.0, 4.2.0 to before 4.13.0, and 5.0.0 to before 5.4.0, the default configuration of startStandaloneServer from @apollo/server/standalone is vulnerable to denial of service (DoS) attacks through specially crafted request bodies with exotic character set encodings. This issue does not affect users that use @apollo/server as a dependency for integration packages, like @as-integrations/express5 or @as-integrations/next, only direct usage of startStandaloneServer.

Scores

CVSS	Score	Vector	Source
3.1	7.5 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	GitHub_M

Weaknesses

CWE-1333 Inefficient Regular Expression Complexity

Affected Products

Product	Versions
apollo-serverapollographql	>= 2.0.0, <= 3.13.0Affected >= 4.2.0, < 4.13.0Affected >= 5.0.0, < 5.4.0Affected

References

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