CVE-2026-31865

MEDIUM

Elysia Cookie Value Prototype Pollution

Title source: cna

Description

Elysia is a Typescript framework for request validation, type inference, OpenAPI documentation, and client-server communication. Prior to version 1.4.27, an Elysia cookie can be overridden by prototype pollution , eg. `__proto__`. This issue is patched in 1.4.27. As a workaround, use t.Cookie validation to enforce validation value and/or prevent iterable over cookie if possible.

Scores

CVSS v3 6.5
EPSS 0.0002
EPSS Percentile 4.8%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Details

CWE
CWE-1321
Status published
Products (2)
elysiajs/elysia < 1.4.27 (2 CPE variants)
npm/elysia 0 - 1.4.27npm
Published Mar 18, 2026
Tracked Since Mar 18, 2026