CVE-2026-33490

H3 is a minimal H(TTP) framework. In versions 2.0.0-0 through 2.0.1-rc.16, the `mount()` method in h3 uses a simple `startsWith()` check to determine whether incoming requests fall under a mounted sub-application's path prefix. Because this check does not verify a path segment boundary (i.e., that the next character after the base is `/` or end-of-string), middleware registered on a mount like `/admin` will also execute for unrelated routes such as `/admin-public`, `/administrator`, or `/adminstuff`. This allows an attacker to trigger context-setting middleware on paths it was never intended to cover, potentially polluting request context with unintended privilege flags. Version 2.0.2-rc.17 contains a patch.

CVSS v3 3.7 LOW

3.7^/10

CVSS v3 : LOW

Vector :

Exploitability : 2.2 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact LOW

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/h3js/h3/security/advisories/GHSA-2j6q-whv2-gh6w	Exploit Mitigation Vendor Advisory
https://github.com/h3js/h3/security/advisories/GHSA-2j6q-whv2-gh6w	Exploit Mitigation Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:h3:h3:2.0.1:rc1::::node.js::*
	cpe:2.3:a:h3:h3:2.0.1:rc10::::node.js::*
	cpe:2.3:a:h3:h3:2.0.1:rc11::::node.js::*
	cpe:2.3:a:h3:h3:2.0.1:rc12::::node.js::*
	cpe:2.3:a:h3:h3:2.0.1:rc13::::node.js::*
	cpe:2.3:a:h3:h3:2.0.1:rc14::::node.js::*
	cpe:2.3:a:h3:h3:2.0.1:rc15::::node.js::*
	cpe:2.3:a:h3:h3:2.0.1:rc16::::node.js::*
	cpe:2.3:a:h3:h3:2.0.1:rc2::::node.js::*
	cpe:2.3:a:h3:h3:2.0.1:rc3::::node.js::*
	cpe:2.3:a:h3:h3:2.0.1:rc4::::node.js::*
	cpe:2.3:a:h3:h3:2.0.1:rc5::::node.js::*
	cpe:2.3:a:h3:h3:2.0.1:rc6::::node.js::*
	cpe:2.3:a:h3:h3:2.0.1:rc7::::node.js::*
	cpe:2.3:a:h3:h3:2.0.1:rc8::::node.js::*
	cpe:2.3:a:h3:h3:2.0.1:rc9::::node.js::*

History

No history.

Information

Published : 2026-03-26 18:16

Updated : 2026-06-17 10:37

NVD link : CVE-2026-33490

Mitre link : CVE-2026-33490

CVE.ORG link : CVE-2026-33490

JSON object : View

Products Affected

h3

h3

CWE

CWE-706

Use of Incorrectly-Resolved Name or Reference

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In versions 2.0.0-0 through 2.0.1-rc.16, the `mount()` method in h3 uses a simple `startsWith()` check to determine whether incoming requests fall under a mounted sub-application's path prefix. Because this check does not verify a path segment boundary (i.e., that the next character after the base is `/` or end-of-string), middleware registered on a mount like `/admin` will also execute for unrelated routes such as `/admin-public`, `/administrator`, or `/adminstuff`. This allows an attacker to trigger context-setting middleware on paths it was never intended to cover, potentially polluting request context with unintended privilege flags. Version 2.0.2-rc.17 contains a patch."}, {"lang": "es", "value": "H3 es un framework H(TTP) m\u00ednimo. En las versiones 2.0.0-0 hasta la 2.0.1-rc.16, el m\u00e9todo 'mount()' en h3 usa una simple verificaci\u00f3n 'startsWith()' para determinar si las solicitudes entrantes caen bajo el prefijo de ruta de una subaplicaci\u00f3n montada. Debido a que esta verificaci\u00f3n no verifica un l\u00edmite de segmento de ruta (es decir, que el siguiente car\u00e1cter despu\u00e9s de la base es '/' o el final de la cadena), el middleware registrado en un montaje como '/admin' tambi\u00e9n se ejecutar\u00e1 para rutas no relacionadas como '/admin-public', '/administrator' o '/adminstuff'. Esto permite a un atacante activar middleware de configuraci\u00f3n de contexto en rutas que nunca se pretendi\u00f3 cubrir, potencialmente contaminando el contexto de la solicitud con indicadores de privilegio no deseados. 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