http-proxy-middleware `router` host+path substring matching allows Host-header-driven backend routing bypass
Priority HIGH 70CWE-187Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- —
- Confidentiality · integrity · availability
- None · Low · None
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub.
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.
Why it matters now
Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00378 31st percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed http-proxy-middleware (chimurai): 4.1.0, 3.0.6, 2.0.10http-proxy-middleware (npm): 3.0.6, 4.1.0, 2.0.10
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| chimurai | http-proxy-middleware | 4.0.0 to before 4.1.0; 3.0.0 to before 3.0.6; 0.16.0 to before 2.0.10 | 4.1.0, 3.0.6, 2.0.10 | Patch available | CNA |
| — | http-proxy-middleware (npm) | 3.0.0 to before 3.0.6 | 3.0.6 | Patch available | GHSA-64mm-vxmg-q3vj |
| — | http-proxy-middleware (npm) | 4.0.0 to before 4.1.0 | 4.1.0 | Patch available | GHSA-64mm-vxmg-q3vj |
| — | http-proxy-middleware (npm) | 0.16.0 to before 2.0.10 | 2.0.10 | Patch available | GHSA-64mm-vxmg-q3vj |
- http-proxy-middleware Vendorchimurai Affected 4.0.0 to before 4.1.0; 3.0.0 to before 3.0.6; 0.16.0 to before 2.0.10 Fixed in 4.1.0, 3.0.6, 2.0.10 Patch available CNA
- http-proxy-middleware (npm) Vendor— Affected 3.0.0 to before 3.0.6 Fixed in 3.0.6 Patch available GHSA-64mm-vxmg-q3vj
- http-proxy-middleware (npm) Vendor— Affected 4.0.0 to before 4.1.0 Fixed in 4.1.0 Patch available GHSA-64mm-vxmg-q3vj
- http-proxy-middleware (npm) Vendor— Affected 0.16.0 to before 2.0.10 Fixed in 2.0.10 Patch available GHSA-64mm-vxmg-q3vj
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:chimurai:http-proxy-middleware:*:*:*:*:*:*:*:* | 0.16.0 to before 2.0.10; 3.0.0 to before 3.0.6; 4.0.0 to before 4.1.0 | Vulnerable | chimurai |
- cpe:2.3:a:chimurai:http-proxy-middleware:*:*:*:*:*:*:*:* Versions 0.16.0 to before 2.0.10; 3.0.0 to before 3.0.6; 4.0.0 to before 4.1.0 Vulnerable ·chimurai
Remediation
- Fix · CNA http-proxy-middleware (chimurai) Fixed in 4.1.0, 3.0.6, 2.0.10
- Fix · GHSA-64mm-vxmg-q3vj http-proxy-middleware (npm) Fixed in 3.0.6 Advisory →
- Fix · GHSA-64mm-vxmg-q3vj http-proxy-middleware (npm) Fixed in 4.1.0 Advisory →
- Fix · GHSA-64mm-vxmg-q3vj http-proxy-middleware (npm) Fixed in 2.0.10 Advisory →
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
Not affected: 30 products
- Cryostat 4
- Gatekeeper 3
- Migration Toolkit for Applications 8
- Migration Toolkit for Containers
- Node HealthCheck Operator
- OpenShift Lightspeed
- OpenShift Pipelines
- OpenShift Service Mesh 2
- OpenShift Service Mesh 3
- Red Hat AMQ Broker 7
- Red Hat Ansible Automation Platform 2
- Red Hat Build of Podman Desktop
- Red Hat Connectivity Link 1
- Red Hat Data Grid 8
- Red Hat Developer Hub 1
- Red Hat Discovery 2
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat Enterprise Linux AI (RHEL AI) 3
- Red Hat Fuse 7
- Red Hat OpenShift AI (RHOAI)
- Red Hat OpenShift Container Platform 4
- Red Hat OpenShift Container Platform 5
- Red Hat OpenShift Virtualization 4
- Red Hat Quay 3
- Red Hat Trusted Artifact Signer
- Red Hat Trusted Profile Analyzer
- Red Hat build of Apache Camel - HawtIO 4
- Red Hat build of Apache Camel for Spring Boot 4
- Self-service automation portal 2
Timeline
- 2026-10-02 Threatist record created from CVE-2026-55602
- 2026-10-03 Alias added: GHSA-64mm-vxmg-q3vj
- 2026-10-27 Affected versions changed · Red Hat
- 2026-10-30 Affected versions changed · Red Hat
References
More chimurai Http-proxy-middleware vulnerabilities
- TI-2024-14292 Uncontrolled resource consumption in http-proxy-middleware CVSS 4.0HIGH 8.7
- TI-2026-40137 http-proxy-middleware: multipart/form-data field injection via unescaped CRLF in `fixRequestBody` CVSS 3.1HIGH 7.5
- TI-2025-24005 In http-proxy-middleware before 2.0.9 and 3.x before 3.0.5, fixRequestBody proceeds even if bodyParser has failed. CVSS 3.1MEDIUM 5.3
- TI-2025-24004 In http-proxy-middleware before 2.0.8 and 3.x before 3.0.4, writeBody can be called twice because "else if" is not used. CVSS 3.1MEDIUM 5.3
Sources
- CVE-2026-55602 · CVE Program
- CVE-2026-55602 · NVD
- FIRST EPSS
- GHSA-64mm-vxmg-q3vj · GitHub Advisory Database · CC BY 4.0
- CVE-2026-55602 · Red Hat security data · CC BY 4.0
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