CVE-2026-31865
MEDIUM6.5EPSS 0.02%Elysia Cookie Value Prototype Pollution
Published: 3/17/2026Modified: 3/19/2026
Also known as:GHSA-8hq9-phh3-p2wp
Description
### Impact Elysia cookie can be overridden by prototype pollution , eg. `__proto__` Sending cookie with the follows name can override cookie value: ```bash __proto__=%7B%22injected%22%3A%22polluted%22%7D ``` ### Patches Patched by 1.4.27 ### Workarounds 1. Use t.Cookie validation to enforce validation value 2. Prevent iterable over cookie if possible
Affected packages (1)
- npm/elysiafrom 0, < 1.4.27
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM6.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N |