CVE-2026-55602 (GCVE-0-2026-55602)

Vulnerability from cvelistv5 – Published: 2026-06-22 15:58 – Updated: 2026-06-23 14:18
VLAI
Title
http-proxy-middleware `router` host+path substring matching allows Host-header-driven backend routing bypass
Summary
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.
Severity
6.9 (Medium)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
SSVC
Exploitation: poc Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-06-23 14:17 UTC
CWE
  • CWE-20 - Improper Input Validation
  • CWE-187 - Partial String Comparison
Assigner
References
Impacted products
Vendor Product Version
chimurai http-proxy-middleware Affected: >= 4.0.0, < 4.1.0
Affected: >= 3.0.0, < 3.0.6
Affected: >= 0.16.0, < 2.0.10
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