CVE-2024-21536 — http-proxy-middleware
Fix: chimurai/http-proxy-middleware@0b4274eCVE-2024-21536 is a Uncontrolled Resource Consumption vulnerability in http-proxy-middleware. 1 public exploit reference exists, so weaponization risk is real. A fix is available for http-proxy-middleware — see the affected versions and patch details below.
Denial of service in http-proxy-middleware
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for CVE-2024-21536.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
http-proxy-middlewarenpmDescription
Versions of the package http-proxy-middleware before 2.0.7, from 3.0.0 and before 3.0.3 are vulnerable to Denial of Service (DoS) due to an UnhandledPromiseRejection error thrown by micromatch. An attacker could kill the Node.js process and crash the server by making requests to certain paths.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | http-proxy-middleware | all versions | 2.0.7npm install http-proxy-middleware@2.0.7 |
| 📦npm | http-proxy-middleware | ≥ 3.0.0&&< 3.0.3 | 3.0.3npm install http-proxy-middleware@3.0.3 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for http-proxy-middleware, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update http-proxy-middleware to 2.0.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-21536 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2024-21536 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2024-21536. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
| Product | Fixed in | Advisory |
|---|---|---|
| Discovery 1 for RHEL 9 | discovery/discovery-server-rhel9:1.12.0-1 | RHSA-2025:1249 |
| Red Hat Advanced Cluster Security 4.5 | advanced-cluster-security/rhacs-central-db-rhel8:4.5.9-1 | RHSA-2025:3928 |
| Red Hat Advanced Cluster Security 4.6 | advanced-cluster-security/rhacs-central-db-rhel8:4.6.5-1 | RHSA-2025:3929 |
| Red Hat Advanced Cluster Security 4.7 | advanced-cluster-security/rhacs-central-db-rhel8:4.7.2-2 | RHSA-2025:3930 |
| Red Hat Developer Hub 1.3 on RHEL 9 | rhdh/rhdh-hub-rhel9:1.3-124 | RHBA-2024:9054 |
| Red Hat Migration Toolkit for Containers 1.8 | rhmtc/openshift-migration-ui-rhel8:v1.8.7-2 | RHSA-2025:8510 |
| Red Hat OpenShift Service Mesh 2.6 for RHEL 8 | openshift-service-mesh/grafana-rhel8:2.6.3-2 | RHSA-2024:9627 |
| RHODF-4.14-RHEL-9 | odf4/ocs-client-console-rhel9:v4.14.18-2 | RHSA-2025:8551 |
Frequently Asked Questions
Is CVE-2024-21536 in your dependencies?
O3 Security finds CVE-2024-21536 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.