CVE-2026-33490

MEDIUM EPSS 14.8%
Published Mar 26, 20263mo ago · Modified Jun 17, 20262w ago
5.3 CVSS 3.1
Medium
Find Similar
Published Mar 26, 2026 3mo ago
Last Modified Jun 17, 2026 2w ago

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.

CVSS Details

Base Score
5.3
Exploitability
3.9
Impact
1.4
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality None
Integrity Low
Availability None

Threat Intelligence

EPSS Exploit Probability
14.8% percentile
Exploit & Patch Status
Public Exploit Known
No Patch Available

Weaknesses 1

CWE-706

Affected Products 16

VendorProductVersionRange
h3h32.0.1any
h3h32.0.1any
h3h32.0.1any
h3h32.0.1any
h3h32.0.1any
h3h32.0.1any
h3h32.0.1any
h3h32.0.1any
h3h32.0.1any
h3h32.0.1any
h3h32.0.1any
h3h32.0.1any
h3h32.0.1any
h3h32.0.1any
h3h32.0.1any
h3h32.0.1any

References 1

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

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.