SecuriTricks - CVE-2026-33490

Description

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.

Product(s) Impacted

Vendor	Product	Versions
H3	H3	2.0.0-2.0.1-rc.16, 2.0.2-rc.17

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-706

Use of Incorrectly-Resolved Name or Reference

The product uses a name or reference to access a resource, but the name/reference resolves to a resource that is outside of the intended control sphere.

*CPE(s)

Affected systems and software identified for this CVE.

Type	Vendor	Product	Version	Update	Edition	Language	Software Edition	Target Software	Target Hardware	Other Information
a	h3	h3	2.0.0-2.0.1-rc.16	/	/	/	/	/	/	/
a	h3	h3	2.0.2-rc.17	/	/	/	/	/	/	/

References

https://github.com/h3js/h3/security/advisories/GHSA-2j6q-whv2-gh6w

CVSS Score

3.7 / 10

CVSS Data - 3.1

Attack Vector: NETWORK
Attack Complexity: HIGH
Privileges Required: NONE
Scope: UNCHANGED
Confidentiality Impact: NONE
Integrity Impact: LOW
Availability Impact: NONE

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

View Vector String

Timeline

Published: March 26, 2026, 6:16 p.m.
Last Modified: March 26, 2026, 7:17 p.m.

Status : Received

CVE has been recently published to the CVE List and has been received by the NVD.

More info

Source

[email protected]

CVE-2026-33490