/ 
Plack-1.0055
⭐ Starred 488 / Plack::Middleware::ErrorDocument
Security Advisories (1)
CVE-2026-115825 (2026-10-25)

HTTP::Server::PSGI versions before 1.0056 for Perl allow a single request to crash the server by declaring a large Content-Length. The request body is read with sysread() calls sized by the remaining Content-Length. Perl grows the read buffer to the requested length before any data arrives, so the server tries to allocate as much memory as the client declares. A remote attacker can send one request with a large Content-Length and a few body bytes, and perl exits with an out-of-memory error before the application is called. HTTP::Server::PSGI runs as a single process, so the server stays down until restarted.

NAME

Plack::Middleware::ErrorDocument - Set Error Document based on HTTP status code

SYNOPSIS

# in app.psgi
use Plack::Builder;

builder {
    enable "Plack::Middleware::ErrorDocument",
        500 => '/uri/errors/500.html', 404 => '/uri/errors/404.html',
        subrequest => 1;
    $app;
};

DESCRIPTION

Plack::Middleware::ErrorDocument allows you to customize error screen by setting paths (file system path or URI path) of error pages per status code.

CONFIGURATIONS

subrequest

A boolean flag to serve error pages using a new GET sub request. Defaults to false, which means it serves error pages using file system path.

builder {
    enable "Plack::Middleware::ErrorDocument",
        502 => '/home/www/htdocs/errors/maint.html';
    enable "Plack::Middleware::ErrorDocument",
        404 => '/static/404.html', 403 => '/static/403.html', subrequest => 1;
    $app;
};

This configuration serves 502 error pages from file system directly assuming that's when you probably maintain database etc. but serves 404 and 403 pages using a sub request so your application can do some logic there like logging or doing suggestions.

When using a subrequest, the subrequest should return a regular '200' response.

AUTHOR

Tatsuhiko Miyagawa

SEE ALSO