CVE-2024-21536 Denial of service in http-proxy-middleware
An attacker can crash the Node.js server by sending requests to specific paths, causing a Denial of Service via an unhandled promise rejection.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2024-21536?
CVE-2024-21536 is a high-severity denial of service vulnerability in http-proxy-middleware, published on 19 Oct 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-400
Which versions are affected by CVE-2024-21536?
4 open source packages ship an affected version, including http-proxy-middleware. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
http-proxy-middleware npm | All versions | 2.0.7 |
http-proxy-middleware npm | All versions | 2.0.7 |
http-proxy-middleware npm | From 3.0.0 | 3.0.3 |
http-proxy-middleware npm | From 3.0.0 | 3.0.3 |
Products include Chimurai Http-Proxy-Middleware.
How do I fix CVE-2024-21536?
Upgrade http-proxy-middleware to a fixed version for your release line: 2.0.7 or 3.0.3.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2024-21536 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2024-21536 exists.
Other vulnerabilities in http-proxy-middleware
- CVE-2026-55603 http-proxy-middleware: multipart/form-data field injection via unescaped CRLF in `fixRequestBody`
- CVE-2026-55602 http-proxy-middleware `router` host+path substring matching allows Host-header-driven backend routing bypass
- CVE-2025-32996 http-proxy-middleware can call writeBody twice because "else if" is not used
- CVE-2025-32997 http-proxy-middleware allows fixRequestBody to proceed even if bodyParser has failed
Sources
Also known as CLSA-2026-1774657386, CLSA-2026-1776299658, CLSA-2026-1784164086, CLSA-2026-1784164093, CLSA-2026-1784596275, GHSA-c7qv-q95q-8v27 and 1 more.