CVE-2026-55602

Home/CVE/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-middlewar

CVE

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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-middlewar

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.

Monitor

⚠ NVD has not scored this CVE yet - manual triage required (common for recent CVEs)

No Sigma yet — build one → YARA rules0

Look this up elsewhere - one-click external pivots

NVD CVE.org CISA Exploit-DB GitHub PoC VulnCheck KEV GreyNoise

▸ How to read a CVE - triage first, then detect and patch

This page is every public fact about CVE-2026-55602, cross-linked. Its job is to answer one question fast - does this need my attention now? - and then hand you the two things you do about it. Here is how an analyst reads it.

Triage: should I act now? Four signals, and they are not interchangeable:

CVSSseverity - how bad it is IF exploited, 0-10. A high CVSS alone is not urgency; a flaw can be a perfect 10 and never actually be attacked. EPSSprobability - a model’s estimate of the chance it is exploited in the next 30 days, 0-1. This is the “will it actually happen” signal. CISA KEVconfirmed - it is being exploited in the wild right now. The strongest signal on the page; KEV beats any score. Weaponisedavailability - public exploits / PoCs, and especially Metasploit modules rated Excellent / Great. Reliable, packaged exploit code means low-skill attackers can use it today.

How they combine: KEV, or a dependable Metasploit module, means patch now regardless of CVSS. High CVSS + low EPSS + no exploit is real but not an emergency - schedule it. Low CVSS but KEV-listed still gets patched now. The verdict above already weighed these for you; this is how it got there.

Then what - two workflows:

Detectwhen you cannot patch today, follow this CVE to the ATT&CK techniques it enables, then Build a SIEM detection (the green button) - author a rule, test it in Atomic, deploy it. That buys visibility while the patch waits. PatchAffected products / packages tell you if you are exposed; Fixed versions by distribution and Vendor advisories give the exact version that closes it.

Reading order for the panels below: verdict + badges, then Public exploits / Metasploit (is it weaponised), then ATT&CK techniques + Sigma / IDS rules (can I detect it), then Affected products / packages + Fixed versions (am I exposed, what patches it), then Threat actors / IOCs (who uses it), then Scoring & timeline / references (the evidence).

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ATT&CK techniques

Techniques this CVE enables. Pills with a solid outline are high confidence - named directly in ATT&CK or Nuclei, or human-curated by CTID; the rest are inferred from the weakness type using MITRE's CVE Mapping Methodology and the CWE → CAPEC chain. Broad, generic-weakness guesses are filtered out. A small N× marks a technique that N independent sources agree on.

T1027 · Obfuscated Files or Information T1036.001 · Invalid Code Signature T1539 · Steal Web Session Cookie T1553.002 · Code Signing T1574.006 · Dynamic Linker Hijacking T1574.007 · Path Interception by PATH Environment Variable T1690 · Prevent Command History Logging

▤ Build a SIEM detection for these techniques

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CAPEC attack patterns

Attack patterns this CVE enables - the bridge from weakness to ATT&CK technique.

CAPEC-CAPEC-10 · Buffer Overflow via Environment Variables CAPEC-CAPEC-101 · Server Side Include (SSI) Injection CAPEC-CAPEC-104 · Cross Zone Scripting CAPEC-CAPEC-108 · Command Line Execution through SQL Injection CAPEC-CAPEC-109 · Object Relational Mapping Injection CAPEC-CAPEC-110 · SQL Injection through SOAP Parameter Tampering CAPEC-CAPEC-120 · Double Encoding CAPEC-CAPEC-13 · Subverting Environment Variable Values CAPEC-CAPEC-135 · Format String Injection CAPEC-CAPEC-136 · LDAP Injection CAPEC-CAPEC-14 · Client-side Injection-induced Buffer Overflow CAPEC-CAPEC-153 · Input Data Manipulation

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Weakness Classification

CWE-187Partial String Comparison

CWE-20Improper Input Validation

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Affected Packages

Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.

npm http-proxy-middleware MEDIUM fixed in 4.1.0

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Related CVEs

CVEs linked to this one by a shared weakness (CWE) or affected product - joins on data already in the engine, with the reason shown per row. Not a guess.

CVE-2022-31802 In CODESYS Gateway Server V2 for versions prior to V2.3.9.38 only a part of the ... same CWE-187 CRITICAL CVE-2024-39742 IBM MQ Operator 3.2.2 and IBM MQ Operator 2.0.24 could allow a user to bypass au... same CWE-187 HIGH CVE-2024-41110 Moby is an open-source project created by Docker for software containerization. ... same CWE-187 CRITICAL CVE-2025-23384 A vulnerability has been identified in RUGGEDCOM RM1224 LTE(4G) EU (6GK6108-4AM0... same CWE-187 LOW CVE-1999-0265 ICMP redirect messages may crash or lock up a host. same CWE-20 CVE-1999-0726 An attacker can conduct a denial of service in Windows NT by executing a program... same CWE-20 CVE-1999-0918 Denial of service in various Windows systems via malformed, fragmented IGMP pack... 3 same CWE-20 CVE-1999-0721 Denial of service in Windows NT Local Security Authority (LSA) through a malform... same CWE-20

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References & Sources

Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.

https://github.com/chimurai/http-proxy-middleware/security/advisories/GHSA-64mm-vxmg-q3vj