CVE-2026-23897: Apollographql Apollo Server

High severity, CVSS 7.5. EPSS: 0.7% chance of exploitation in the next 30 days.

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.

Affected products

• Apollographql Apollo Server: from 2.0.0, up to and including 3.13.0; from 4.2.0, before 4.13.0 (fixed in 4.13.0); from 5.0.0, before 5.4.0 (fixed in 5.4.0)

Published 2026-02-04. Last modified 2026-06-17.