CVE-2026-31865
Elysia Cookie Value Prototype Pollution
Vexday Risk Score
13Low
SSVC decision (CISA)
Track
No exploitation signal → monitor
CVSS 6.5EPSS 0.2%KEV nãoPoC —Nuclei —Metasploit —Patch —
Lifecycle
18 Mar 2026Published on NVD
Recommendation: Monitor — no exploitation signal at the moment.
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Affected products
elysiajs · elysiaWant to know if your infrastructure is exposed to this?
Talk to TrueHacking →