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Fencer Vulns
high 7.5

CVE-2026-55603 json

http-proxy-middleware: multipart/form-data field injection via unescaped CRLF in `fixRequestBody`

published 2026-06-18 4 mo ago modified 2026-10-25 14 d ago also GHSA-gcq2-9pq2-cxqm , EUVD-2026-38349

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 21%
public exploits
0
none known

Summary

http-proxy-middleware is node.js http-proxy middleware. From 3.0.4 until 3.0.7 and 4.1.1, fixRequestBody() is the library's documented helper for re-emitting a request body that was already consumed by a body parser. When the outgoing Content-Type is multipart/form-data, it rebuilds the body with handlerFormDataBodyData(), which interpolates each req.body key and value directly into the multipart wire format without neutralizing CR/LF. A \r\n inside a value (or key) lets an attacker close the current part and inject an entirely new form part. Because the proxy's own body parser saw a single opaque value, any gateway-side policy or validation performed on req.body is evaluated against a different set of fields than the upstream backend ultimately parses a request/parameter desynchronization across the trust boundary. This vulnerability is fixed in 3.0.7 and 4.1.1.

Patch / fix

  • npm http-proxy-middleware 3.0.7, 4.1.1
  • chimurai http-proxy-middleware 3.0.7, 4.1.1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-55603 updated cvss 7.5

http-proxy-middleware: http-proxy-middleware: Data integrity compromise via CR/LF injection

  • Red Hat Trusted Profile Analyzer rhtpa/rhtpa-trustification-service-rhel9
    affected: workaround, no fix available
  • Red Hat Migration Toolkit for Applications 8.1 mta/mta-ui-rhel9 1785169013
    fixed: vendor fix RHSA-2026:50300
  • Red Hat Trusted Artifact Signer 1.3 rhtas/rhtas-console-ui-rhel9 1784105894
    fixed: vendor fix RHSA-2026:42085
  • Red Hat Cryostat 4 http-proxy-middleware, cryostat-openshift-console-plugin-npm Red Hat Gatekeeper 3 gatekeeper/gatekeeper-rhel9 Red Hat Migration Toolkit for Applications 8 mta/mta-ui-rhel8 Red Hat Migration Toolkit for Containers rhmtc/openshift-migration-ui-rhel8 Red Hat Node HealthCheck Operator workload-availability/node-healthcheck-rhel9-operator, workload-availability/node-healthcheck-operator-bundle, workload-availability/node-healthcheck-must-gather-rhel9 Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-console-plugin-rhel9, openshift-lightspeed/lightspeed-console-plugin-419-rhel9, openshift-lightspeed/lightspeed-console-plugin-pf5-rhel9
    +17 more products
    Red Hat OpenShift Pipelines openshift-pipelines/pipelines-hub-ui-rhel8, openshift-pipelines/pipelines-hub-ui-rhel9, openshift-pipelines/pipelines-console-plugin-rhel8, openshift-pipelines/pipelines-console-plugin-rhel9, openshift-pipelines/pipelines-console-plugin-pf5-rhel9 Red Hat OpenShift Service Mesh 2 openshift-service-mesh/kiali-rhel8, openshift-service-mesh/kiali-ossmc-rhel8 Red Hat OpenShift Service Mesh 3 openshift-service-mesh/kiali-rhel9, openshift-service-mesh/kiali-ossmc-rhel9, openshift-service-mesh/kiali-rhel9-operator, openshift-service-mesh/kiali-operator-bundle Red Hat AMQ Broker 7 http-proxy-middleware Red Hat Ansible Automation Platform 2 automation-eda-controller, ansible-automation-platform-26/gateway-rhel9, ansible-automation-platform-27/gateway-rhel9, ansible-automation-platform-24/lightspeed-rhel8, ansible-automation-platform-25/lightspeed-rhel8, ansible-automation-platform-26/lightspeed-rhel9, +1 more Red Hat build of Apache Camel - HawtIO 4 http-proxy-middleware Red Hat build of Apache Camel for Spring Boot 4 http-proxy-middleware Red Hat Build of Podman Desktop rh-podman-desktop.git Red Hat Connectivity Link 1 rhcl-1/rhcl-console-plugin-rhel9 Red Hat Data Grid 8 http-proxy-middleware Red Hat Developer Hub 1 rhdh/rhdh-hub-rhel9 Red Hat Discovery 2 discovery/discovery-ui-rhel9 Red Hat Enterprise Linux 8 pcs, grafana, pcs-snmp, grafana-loki, grafana-mssql, grafana-mysql, +10 more Red Hat Enterprise Linux 9 pcs, pcs-snmp Red Hat Enterprise Linux AI (RHEL AI) 3 rhelai3/bootc-cuda-rhel9, rhelai3/bootc-rocm-rhel9, rhelai3/bootc-gaudi-rhel9, rhelai3/disk-image-cuda-rhel9 Red Hat Fuse 7 http-proxy-middleware Red Hat Migration Toolkit for Applications 8.1 mta/mta-cli-rhel9 1785171639, mta/mta-hub-rhel9 1784313347, mta/mta-rhel9-operator 1785168960, mta/mta-operator-bundle 1785177948, mta/mta-analyzer-addon-rhel9 1784900791, mta/mta-platform-addon-rhel9 1784312255, +5 more
    not affected: vulnerable code not present
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-mlflow-rhel9
    not affected: component not present
  • Red Hat OpenShift Container Platform 4 openshift4/ose-console, openshift4/ose-console-rhel9, openshift4/ose-agent-installer-ui-rhel9 Red Hat OpenShift Container Platform 5 openshift5/ose-console-rhel9, openshift5/ose-agent-installer-ui-rhel9 Red Hat OpenShift Virtualization 4 container-native-virtualization/kubevirt-console-plugin, container-native-virtualization/kubevirt-console-plugin-rhel9 Red Hat Quay 3 quay/quay-rhel8 Red Hat Trusted Artifact Signer 1.3 rhtas/rhtas-console-rhel9 1784105848 Red Hat Self-service automation portal 2 ansible-automation-platform/automation-portal, ansible-automation-platform/bootc-automation-portal-rhel9
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
4 mo ago

Exploit prediction

0.29% chance of exploitation in the next 30 days, higher than 21% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/chimurai/http-proxy-middleware/security/advisories/GHSA-gcq2-9pq2-cxqm referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:N
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:N

Affected packages

ecosystem package affected fixed in
npm http-proxy-middleware
>=3.0.4, <3.0.7
>=4.0.0, <4.1.1
3.0.7
4.1.1

Affected products

  • chimurai http-proxy-middleware

Classification

Weakness
  • CWE-93 Improper Neutralization of CRLF Sequences

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.