CVE-2025-66457: Elysia is a Typescript framework for request validation, type inference, OpenAPI documentation and client-serv

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HIGH 8.8UPGRADE

CVE-2025-66457 is a high-severity flaw (CVSS 8.8) affecting elysia. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Elysia is a Typescript framework for request validation, type inference, OpenAPI documentation and client-server communication. Versions 1.4.17 and below are subject to arbitrary code execution from cookie config. When dynamic cookies are enabled (e.g. there an existing cookie schema), the cookie config is injected into the compiled route without first being sanitised. Availability of this exploit is generally low, but when combined with GHSA-hx

Why this priority

High severity
Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.8% (top 43%)
CISA exploited list	No
Weakness	CWE-94
Published	2025-12-09
Last modified	2026-10-14

Publisher (CNA): GitHub, Inc. · Vendor: elysiajs

Last updated 2026-10-14 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-12-09 20:15 UTCPublished CVE record published
2026-10-14 21:10 UTCUpdated Record last modified

elysiajs elysia UPGRADE

Affected: < 1.4.18

Fixed in: 1.4.18

Safe to downgrade to: no unaffected older release

1. Check installed version

npm ls elysia

2. UPGRADE to 1.4.18

npm install elysia@">=1.4.18"

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-66457?

elysia: upgrade to 1.4.18. Exact commands for each OS are on this page.

Is CVE-2025-66457 being exploited?

CVE-2025-66457 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-66457 affect?

CVE-2025-66457 affects elysia. Severity is high (CVSS 8.8). Elysia is a Typescript framework for request validation, type inference, OpenAPI documentation and client-server communication. Versions 1.4.17 and below are subject to arbitrary code execution from cookie config. When dynamic cookies are e

How urgent is CVE-2025-66457?

Priority 50/100. High severity; Public exploit reference

Related CVEs

CVE-2025-66456 CRITICAL 9.8 UPGRADE Elysia is a Typescript framework for request validation, type inference, OpenAPI documentation and client-serv
CVE-2026-31865 MEDIUM 6.5 UPGRADE Elysia is a Typescript framework for request validation, type inference, OpenAPI documentation, and client-ser
CVE-2026-30837 HIGH 7.5 UPGRADE Elysia is a Typescript framework for request validation, type inference, OpenAPI documentation and client-serv

References

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