CVE-2026-100724

Published: Set 27, 2026 Last Modified: Set 27, 2026

ExploitDB:

Other exploit source:

Google Dorks:

MEDIUM 6,3

Source: [email protected]

Attack Vector: network

Attack Complexity: low

Privileges Required: none

User Interaction: none

Confidentiality: N/A

Integrity: N/A

Availability: N/A

MEDIUM 5,4

Source: [email protected]

Attack Vector: network

Attack Complexity: high

Privileges Required: none

User Interaction: none

Scope: changed

Confidentiality: low

Integrity: low

Availability: none

Description

AI Translation Available

http4k (Maven package org.http4k:http4k-core) before 6.49.0.0, 5.42.0.0 and 4.51.0.0 uses substring (Contains) matching on the Host header by default in reverseProxy() and reverseProxyRouting() when dispatching to configured virtual hosts. If these functions are deployed as a public-facing inbound HTTP handler with two or more configured virtual hosts, a remote attacker can supply a Host header that merely contains a configured vhost name (for example Host: admin.evil.com for a vhost configured as 'admin') and be routed to that vhost, bypassing routing-based authorization. The intended outbound-dispatch and test-time uses, where the Host value is set by the calling application, are not affected.