Preliminary research

The Forgotten Bug: How a Node.js Core Design Flaw Enables HTTP Request Splitting

Martino Spagnuolo · Martino Spagnuolo · 27 February 2026

AI-collected research leads through 6 October 2026, including bounded month-by-month reviews of selected social and community sources from January through September. Unranked, incomplete, not community-vetted, and subject to change.

Surveys callbacks and events that permit a Node.js request path to change after constructor validation but before header serialization. Library comparisons and a decoded Express proxy route show how unsafe application assignments can introduce request splitting, with the request lifecycle identifying where validation must actually occur.

Record

Researcher

Martino Spagnuolo

Published by

Martino Spagnuolo

Date

27 February 2026

Format

Advisory

In the archive

• Collected in the 2026 preliminary research sweep

Tags

• nodejs
• header-injection
• request-smuggling
• http
• reverse-proxy
• owasp-a03-2021

This page is the archive's own catalogue record. The research is the work of Martino Spagnuolo, first published at the original source. Preserved copies are kept so the citation survives its host.