elysiajs/elysia · Security

Elysia has a string URL format ReDoS

GHSA ID
GHSA-f45g-68q3-5w8x
CVE ID
CVE-2026-30837
Severity
high
Published
Updated
CVSS
7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v3
7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Description

Impact

t.String({ format: 'url' }) is vulnerable to redos

Repeating a partial url format (protocol and hostname) multiple times cause regex to slow down significantly

'http://a'.repeat(n)

Here's a table demonstrating how long it takes to process repeated partial url format

n repeat elapsed_ms
1024 33.993
2048 134.357
4096 537.608
8192 2155.842
16384 8618.457
32768 34604.139

Patches

Patched by 1.4.26, please kindly update elysia to >= 1.4.26

Here's how long it takes after the patch

n repeat elapsed_ms
1024 0.194
2048 0.274
4096 0.455
8192 0.831
16384 1.632
32768 3.052

Workarounds

  1. It's recommended to always limit URL format to a reasonable length
t.String({
	format: 'url',
	maxLength: 288
})
  1. If a long URL format is necessary, to patch this without updating to 1.4.26, add the following code to any part of your codebase
import { FormatRegistry } from '@sinclair/typebox'

FormatRegistry.Delete('url')
FormatRegistry.Set('url', (value) =>
	/^(?:https?|ftp):\/\/(?:[^\s:@]+(?::[^\s@]*)?@)?(?:(?!(?:10|127)(?:\.\d{1,3}){3})(?!(?:169\.254|192\.168)(?:\.\d{1,3}){2})(?!172\.(?:1[6-9]|2\d|3[0-1])(?:\.\d{1,3}){2})(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])(?:\.(?:1?\d{1,2}|2[0-4]\d|25[0-5])){2}(?:\.(?:[1-9]\d?|1\d\d|2[0-4]\d|25[0-4]))|(?:(?:[a-z0-9\u{00a1}-\u{ffff}]+-)*[a-z0-9\u{00a1}-\u{ffff}]+)(?:\.(?:[a-z0-9\u{00a1}-\u{ffff}]+-)*[a-z0-9\u{00a1}-\u{ffff}]+)*(?:\.(?:[a-z\u{00a1}-\u{ffff}]{2,})))(?::\d{2,5})?(?:\/[^\s]*)?$/iu.test(
		value
	)
)

CWEs

References