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CVE-2025-66457

Elysiajs Elysia code injection

8.8 HIGHPublic exploitEPSS 0.81%
  1. Published9 Dec 2025

Description

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-hxj9-33pp-j2cc, it allows for a full RCE chain. An attack requires write access to either the Elysia app's source code (in which case the vulnerability is meaningless) or write access to the cookie config (perhaps where it is assumed to be provisioned by the environment). This issue is fixed in version 1.4.18.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredLow
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

Elysiajs Elysia< 1.4.18

Remediation

Fixed in
Elysiajs Elysia≥ 1.4.18

References

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Frequently asked

Is CVE-2025-66457 being actively exploited?

CVE-2025-66457 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.81%.

How severe is CVE-2025-66457?

CVE-2025-66457 has a CVSS 3.1 base score of 8.8, rated high. EPSS estimates a 0.81% probability of exploitation.

Which products are affected by CVE-2025-66457?

Affected products include Elysiajs Elysia.

How do I fix CVE-2025-66457?

Upgrade affected software to a fixed version, for example Elysiajs Elysia 1.4.18 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2025-66457 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.