CVE-2026-56669

Elysia v1.4.28 is vulnerable to denial-of-service attacks due to CPU exhaustion in the form data normalization code. Elysia uses `getAll` to retrieve value from FormData. It is called directly relative to the total number of key-value pairs in the form data. The total amount of work the for loop has to do grows quadratically, so doubling the number of unique key-value pairs quadruples the amount of work. In the above PoC, each .getAll call scans through all of the `n` key-value pairs in the form data. Because there are `n` unique keys in the form data, there are .getAll calls, so in total the form data normalizer has to scan `n` x `n` key-value pairs. ### Impact Endpoints using `multipart/form-data` ### Patches 1.4.29 ### Workarounds no 100% confirm workaround beside updating the patch

Elysia v1.4.28 is vulnerable to denial-of-service attacks due to CPU exhaustion in the form data normalization code. Elysia uses `getAll` to retrieve value from FormData. It is called directly relative to the total number of key-value pairs in the form data. The total amount of work the for loop has to do grows quadratically, so doubling the number of unique key-value pairs quadruples the amount of work. In the above PoC, each .getAll call scans through all of the `n` key-value pairs in the form data. Because there are `n` unique keys in the form data, there are .getAll calls, so in total the form data normalizer has to scan `n` x `n` key-value pairs. ### Impact Endpoints using `multipart/form-data` ### Patches 1.4.29 ### Workarounds no 100% confirm workaround beside updating the patch

Elysia es un framework de Typescript para validación de solicitudes, inferencia de tipos, documentación OpenAPI y comunicación cliente-servidor. Antes de la versión 1.4.29, Elysia utiliza getAll en la normalización de datos de formulario para endpoints multipart/form-data, lo que provoca que la cantidad de trabajo crezca cuadráticamente con el número de pares clave-valor únicos y permite el agotamiento de la CPU. Este problema está solucionado en la versión 1.4.29.