CVE-2026-31865
MEDIUMElysia Cookie Value Prototype Pollution
Title source: cnaDescription
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