CVE-2026-31865
Elysia Cookie Value Prototype Pollution
CVSS Score
6.5
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-1321 |
| Vendor | elysiajs |
| Product | elysia |
| Published | Mar 18, 2026 |
| Last Updated | Mar 18, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None
Affected Versions
elysiajs / elysia
< 1.4.27