CVE-2026-56669
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk50th percentile - higher than 50% of all known CVEs
Summary
A vulnerability in Elysia prior to version 1.4.29 causes quadratic CPU workload growth when processing multipart/form-data with many unique key-value pairs. The use of getAll in data normalization leads to CPU exhaustion.
Risk Assessment
An attacker can send a crafted request with a large number of unique key-value pairs, causing excessive CPU usage and potential denial of service (DoS).
Recommendation
Immediately update Elysia to version 1.4.29 or later, which includes a fix that eliminates the quadratic complexity issue.
Other vulnerabilities in Elysia
See all- CVE-2025-66456Critical
Elysia is a TypeScript framework for request validation, type inference, OpenAPI documentation and client-server communication. Versions 1.4.0 through 1.4.16 contain a prototype pollution vulnerability in mergeDeep after merging results of two standard schema validations with the same key. Due to the ordering of merging, there must be an any type that is set as a standalone guard, to allow for the __proto__ prop to be merged. When combined with GHSA-8vch-m3f4-q8jf this allows for a full RCE by an attacker. This issue is fixed in version 1.4.17.
- CVE-2025-66457High
Elysia is a Typescript framework for request validation, type inference, OpenAPI documentation and client-server communication. Versions 1.4.17 and below are subject to arbitrary code execution from cookie config; when dynamic cookies are enabled, the cookie config is injected into the compiled route without first being sanitised. This issue is fixed in version 1.4.18.
Original NVD description (English source)
Elysia is a Typescript framework for request validation, type inference, OpenAPI documentation, and client-server communication. Prior to 1.4.29, Elysia uses getAll in form data normalization for multipart/form-data endpoints, causing the amount of work to grow quadratically with the number of unique key-value pairs and allowing CPU exhaustion. This issue is fixed in version 1.4.29.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS