Description
TinyWeb is a web server (HTTP, HTTPS) written in Delphi for Win32. A vulnerability in versions prior to 2.01 allows unauthenticated remote attackers to bypass the web server's CGI parameter security controls. Depending on the server configuration and the specific CGI executable in use, the impact is either source code disclosure or remote code execution (RCE). Anyone hosting CGI scripts (particularly interpreted languages like PHP) using vulnerable versions of TinyWeb is impacted. The problem has been patched in version 2.01. If upgrading is not immediately possible, ensure `STRICT_CGI_PARAMS` is enabled (it is defined by default in `define.inc`) and/or do not use CGI executables that natively accept dangerous command-line flags (such as `php-cgi.exe`). If hosting PHP, consider placing the server behind a Web Application Firewall (WAF) that explicitly blocks URL query string parameters that begin with a hyphen (`-`) or contain encoded double quotes (`%22`).
Problem types
CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
CWE-88: Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')
Product status
References
github.com/...inyWeb/security/advisories/GHSA-rfx5-fh9m-9jj9
github.com/...ommit/d9dbda8db49da69d2160e1c527e782b73b5ffb6b
github.com/maximmasiutin/TinyWeb/releases/tag/v2.01
www.masiutin.net/tinyweb-cve-2026-27613.html