ZDI 2026-08-13

ZDI-26-578: NGINX HTTP Dav Module Alias Directive Integer Underflow Remote Code Execution Vulnerability

CVE-2026-27654

Machine-generated analysis · WAYSCloud LLM

The advisory notes an integer underflow in the NGINX HTTP Dav module’s alias directive.

Context

The affected component is the NGINX HTTP Dav module’s alias directive. The advisory describes an integer underflow that enables remote code execution without authentication. The CVSS base score is reported as 8.1.

Operator considerations

Check: Verify if the HTTP Dav module is enabled and if the alias directive is configured.
Log: Record requests that target the alias directive to monitor for exploitation attempts.

From Zero Day Initiative ↗

This vulnerability allows remote attackers to execute arbitrary code on affected installations of NGINX. Authentication is not required to exploit this vulnerability. The ZDI has assigned a CVSS rating of 8.1. The following CVEs are assigned: CVE-2026-27654.

Read the full advisory on ZDI →