CVE-2026-30837: Elysia has a string URL format redos

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-03-10 · updated 2026-06-17
Weakness: CWE-1333

Description

Elysia is a Typescript framework for request validation, type inference, OpenAPI documentation and client-server communication. Prior to 1.4.26 , t.String({ format: 'url' }) is vulnerable to ReDoS. Repeating a partial url format (protocol and hostname) multiple times cause regex to slow down significantly. This vulnerability is fixed in 1.4.26.

Affected products

elysiajs elysia: before 1.4.26 — fixed in 1.4.26

How to fix

Upgrade to a fixed version: elysiajs elysia 1.4.26. Check the vendor advisory for mitigations.

References

https://github.com/EdamAme-x/elysia-poc-redos
https://github.com/elysiajs/elysia/security/advisories/GHSA-f45g-68q3-5w8x

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