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Plack-1.0053
⭐ Starred 488 / Plack::Middleware::IIS6ScriptNameFix
Security Advisories (1)
CVE-2026-7381 (2026-04-29)

Plack::Middleware::XSendfile versions through 1.0053 for Perl can allow client-controlled path rewriting. Plack::Middleware::XSendfile allows the variation setting (sendfile type) to be set by the client via the X-Sendfile-Type header, if it is not considered in the middleware constructor or the Plack environment. A malicious client can set the X-Sendfile-Type header to "X-Accel-Redirect" to services running behind nginx reverse proxies, and then set the X-Accel-Mapping to map the path to an arbitrary file on the server. Since 1.0053, Plack::Middleware::XSendfile is deprecated and will be removed from future releases of Plack. This is similar to CVE-2025-61780 for Rack::Sendfile, although Plack::Middleware::XSendfile has some mitigations that disallow regular expressions to be used in the mapping, and only apply the mapping for the "X-Accel-Redirect" type.

NAME

Plack::Middleware::IIS6ScriptNameFix - fixes wrong SCRIPT_NAME and PATH_INFO that IIS6 sets

SYNOPSIS

# in your app.psgi
use Plack::Builder;

builder {
  enable "IIS6ScriptNameFix";
  $app;
};

# Or from the command line
plackup -s FCGI -e 'enable "IIS6ScriptNameFix"' /path/to/app.psgi

DESCRIPTION

This middleware fixes wrong SCRIPT_NAME and PATH_INFO set by IIS6.

OPTIONS

force

By default, this middleware checks if SERVER_SOFTWARE PSGI environment matches what Microsoft IIS server 6-9 would set for FastCGI. By setting force to true (1), this middleware always applies the fix, regardless of the SERVER_SOFTWARE string.

Use this option if the environment is broken similar to IIS, or if the IIS is updated and the regular expression in this module doesn't match any more e.g. you're running IIS 10.

AUTHORS

Florian Ragwitz