CVE-2026-55602

HIGH

http-proxy-middleware `router` host+path substring matching allows Host-header-driven backend routing bypass

Title source: cna
STIX 2.1

Description

http-proxy-middleware is node.js http-proxy middleware. From 0.16.0 until 2.0.10, 3.0.6, and 4.1.0, http-proxy-middleware documents router proxy-table entries as host, path, or host+path selectors, but the host+path implementation uses unanchored substring matching on attacker-controlled request metadata. As a result, a crafted Host header that is only a superstring match for a configured host+path key can still route a request to an unintended backend. This vulnerability is fixed in 2.0.10, 3.0.6, and 4.1.0.

References (1)

Core 1

Scores

CVSS v3 8.6
EPSS 0.0034
EPSS Percentile 26.0%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N

CISA SSVC

Vulnrichment
Exploitation poc
Automatable yes
Technical Impact partial

Details

CWE
CWE-187 CWE-20
Status published
Products (7)
chimurai/http-proxy-middleware 0.16.0 - 2.0.10
chimurai/http-proxy-middleware >= 0.16.0, < 2.0.10
chimurai/http-proxy-middleware >= 3.0.0, < 3.0.6
chimurai/http-proxy-middleware >= 4.0.0, < 4.1.0
npm/http-proxy-middleware 0.16.0 - 2.0.10npm
npm/http-proxy-middleware 3.0.0 - 3.0.6npm
npm/http-proxy-middleware 4.0.0 - 4.1.0npm
Published Jun 22, 2026
Tracked Since Jun 22, 2026