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.
References (2)
Core 2
Core References
X_Refsource_Confirm x_refsource_confirm
https://github.com/elysiajs/elysia/security/advisories/GHSA-8hq9-phh3-p2wp
X_Refsource_Misc x_refsource_misc
https://github.com/elysiajs/elysia/commit/e9d6b1743fa7368ef942dce181f6a089757f6aab
Scores
CVSS v3
6.5
EPSS
0.0002
EPSS Percentile
5.9%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
yes
Technical Impact
partial
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