Summary
Denial of Service in http-proxy
Versions of http-proxy prior to 1.18.1 are vulnerable to Denial of Service. An HTTP request with a long body triggers an ERR_HTTP_HEADERS_SENT unhandled exception that crashes the proxy server. This is only possible when the proxy server sets headers in the proxy request using the proxyReq.setHeader function.
For a proxy server running on http://localhost:3000, the following curl request triggers the unhandled exception:curl -XPOST http://localhost:3000 -d "$(python -c 'print("x"*1025)')"
Recommendation
Upgrade to version 1.18.1 or later
Impact
GHSA-6X33-PW7P-HMPQ has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.18.1); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is GHSA-6X33-PW7P-HMPQ? GHSA-6X33-PW7P-HMPQ is a high-severity security vulnerability in http-proxy (npm), affecting versions < 1.18.1. It is fixed in 1.18.1.
- How severe is GHSA-6X33-PW7P-HMPQ? GHSA-6X33-PW7P-HMPQ has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of http-proxy are affected by GHSA-6X33-PW7P-HMPQ? http-proxy (npm) versions < 1.18.1 is affected.
- Is there a fix for GHSA-6X33-PW7P-HMPQ? Yes. GHSA-6X33-PW7P-HMPQ is fixed in 1.18.1. Upgrade to this version or later.
- Is GHSA-6X33-PW7P-HMPQ exploitable, and should I be worried? Whether GHSA-6X33-PW7P-HMPQ is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether GHSA-6X33-PW7P-HMPQ is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix GHSA-6X33-PW7P-HMPQ? Upgrade
http-proxyto 1.18.1 or later.