CVE-2026-23897
Apollographql Apollo Server 2.0.0 – 3.13.0
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HSummary
CVE-2026-23897 is a high-severity Inefficient Regular Expression Complexity (CWE-1333) vulnerability in Apollographql Apollo Server. Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Endpoint Denial of Service (T1499); ranked at the 47th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-15 (Development Process, Standards, and Tools) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-23897 is a denial-of-service (DoS) vulnerability in Apollo Server, an open-source, spec-compliant GraphQL server compatible with any GraphQL client. It affects the default configuration of startStandaloneServer from the @apollo/server/standalone package in versions 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 flaw arises from specially crafted request bodies using exotic character set encodings and does not impact users integrating @apollo/server via packages like @as-integrations/express5 or @as-integrations/next, only direct usage of startStandaloneServer. The vulnerability is rated 7.5 on the CVSS v3.1 scale (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) and maps to CWE-1333.
Any unauthenticated remote attacker with network access to the server can exploit this vulnerability with low complexity and no user interaction required. By sending malicious requests with exotic encodings, the attacker triggers excessive resource consumption, leading to a denial of service that disrupts server availability.
The official mitigation guidance is detailed in the Apollo Server GitHub security advisory (GHSA-mp6q-xf9x-fwf7), along with fixing commits d25a5bdc377826ad424fcf7f8d1d062055911643 and e9d49d163a86b8a33be56ed27c494b9acd5400a4. Security practitioners should upgrade to patched versions beyond the affected ranges and review deployments using startStandaloneServer directly.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-5364
Vulnerability Data
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…
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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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation can discover inefficient regex patterns via performance or static analysis.
Development standards and tools can require safe regex construction and forbid known exponential patterns.
Denial-of-service protections limit resource exhaustion caused by expensive regex evaluation.
Input validation can constrain data that would otherwise trigger worst-case regex complexity.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing can detect and reject regex patterns with exponential worst-case complexity.
Secure development lifecycle mandates review of algorithmic efficiency, directly addressing ReDoS-prone regex.
Application security requirements can specify input-validation rules that limit regex complexity.
Secure architecture principles encourage avoidance of computationally expensive constructs such as catastrophic backtracking.
Secure coding standards explicitly prohibit or limit the use of inefficient regular expressions.