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Plack-1.0055
⭐ Starred 488 / Plack::Loader::Delayed
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::Loader::Delayed - Delay the loading of .psgi until the first run

SYNOPSIS

plackup -s Starlet -L Delayed myapp.psgi

DESCRIPTION

This loader delays the compilation of specified PSGI application until the first request time. This prevents bad things from happening with preforking web servers like Starlet, when your application manipulates resources such as sockets or database connections in the master startup process and then shared by children.

You can combine this loader with -M command line option, like:

plackup -s Starlet -MCatalyst -L Delayed myapp.psgi

loads the module Catalyst in the master process for the better process management with copy-on-write, however the application myapp.psgi is loaded per children.

Starman since version 0.2000 loads this loader by default unless you specify the command line option --preload-app for the starman executable.

DEVELOPERS

Web server developers can make use of psgi_app_builder attribute callback set in Plack::Handler, to load the application earlier than the first request time.

AUTHOR

Tatsuhiko Miyagawa

SEE ALSO

plackup