Black & White Path

Jul 20, 2026 · Information Security

A 15‑Year‑Old NGINX Map Regex RCE Flaw (CVE‑2026‑42533): Deep Technical Breakdown

A severe remote‑code‑execution vulnerability (CVE‑2026‑42533) in NGINX’s map‑regex handling, present since 2011, lets an attacker trigger a heap overflow and bypass ASLR with a single crafted HTTP request, affecting dozens of directives across both HTTP and Stream modules, and the article details the underlying two‑pass evaluation flaw, exploitation steps, impact assessment, and remediation guidance.