Vulnerability in Apollographql Apollo-Server
CVE-2026-23897
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.
Vulnerability class: ReDoS (Regular Expression Denial of Service)
EPSS: 0.006 (46.5th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
Affected products
- Apollographql Apollo-server — versions >= 2.0.0, <= 3.13.0, >= 4.2.0, < 4.13.0, >= 5.0.0, < 5.4.0
- Apollographql Apollo_server
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Mitigation, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (Patch, x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-23897?
- CVE-2026-23897 is a high-severity vulnerability in Apollographql Apollo-Server, classified under Inefficient Regular Expression Complexity. CVSS score: 7.5/10. Published 2026-02-04.
- How severe is CVE-2026-23897?
- High severity. CVSS v3 base score is 7.5 out of 10.