Affected: Homebrew: mailcatcher

## Summary

`Rack::Multipart::Parser` only wraps the request body in a `BoundedIO` when `CONTENT_LENGTH` is present. When a `multipart/form-data` request is sent without a `Content-Length` header, such as with HTTP chunked transfer encoding, multipart parsing continues until end-of-stream with no total size limit.

For file parts, the uploaded body is written directly to a temporary file on disk rather than being constrained by the buffered in-memory upload limit. An unauthenticated attacker can therefore stream an arbitrarily large multipart file upload and consume unbounded disk space.

This results in a denial of service condition for Rack applications that accept multipart form data.

## Details

`Rack::Multipart::Parser.parse` applies `BoundedIO` only when `content_length` is not `nil`:

```ruby io = BoundedIO.new(io, content_length) if content_length ```

When `CONTENT_LENGTH` is absent, the parser reads the multipart body until EOF without a global byte limit.

Although Rack enforces `BUFFERED_UPLOAD_BYTESIZE_LIMIT` for retained non-file parts, file uploads are handled differently. When a multipart part includes a filename, the body is streamed to a `Tempfile`, and the retained-size accounting is not applied to that file content. As a result, file parts are not subject to the same upload size bound.

An attacker can exploit this by sending a chunked `multipart/form-data` request containing a file part and continuously streaming data without declaring a `Content-Length…

Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Multipart::Parser only wraps the request body in a BoundedIO when CONTENT_LENGTH is present. When a multipart/form-data request is sent without a Content-Length header, such as with HTTP chunked transfer encoding, multipart parsing continues until end-of-stream with no total size limit. For file parts, the uploaded body is written directly to a temporary file on disk rather than being constrained by the buffered in-memory upload limit. An unauthenticated attacker can therefore stream an arbitrarily large multipart file upload and consume unbounded disk space. This results in a denial of service condition for Rack applications that accept multipart form data. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.

Affected: RubyGems: rack

## Summary

`Rack::Multipart::Parser` only wraps the request body in a `BoundedIO` when `CONTENT_LENGTH` is present. When a `multipart/form-data` request is sent without a `Content-Length` header, such as with HTTP chunked transfer encoding, multipart parsing continues until end-of-stream with no total size limit.

For file parts, the uploaded body is written directly to a temporary file on disk rather than being constrained by the buffered in-memory upload limit. An unauthenticated attacker can therefore stream an arbitrarily large multipart file upload and consume unbounded disk space.

This results in a denial of service condition for Rack applications that accept multipart form data.

## Details

`Rack::Multipart::Parser.parse` applies `BoundedIO` only when `content_length` is not `nil`:

```ruby io = BoundedIO.new(io, content_length) if content_length ```

When `CONTENT_LENGTH` is absent, the parser reads the multipart body until EOF without a global byte limit.

Although Rack enforces `BUFFERED_UPLOAD_BYTESIZE_LIMIT` for retained non-file parts, file uploads are handled differently. When a multipart part includes a filename, the body is streamed to a `Tempfile`, and the retained-size accounting is not applied to that file content. As a result, file parts are not subject to the same upload size bound.

An attacker can exploit this by sending a chunked `multipart/form-data` request containing a file part and continuously streaming data without declaring a `Content-Length…

ruby4.0-rubygem-rack-2.2-2.2.23-1.1 on GA media

Security update for rmt-server

Affected: Ubuntu:Pro:14.04:LTS: ruby-rack, Ubuntu:Pro:16.04:LTS: ruby-rack, Ubuntu:Pro:18.04:LTS: ruby-rack, Ubuntu:Pro:22.04:LTS: ruby-rack, Ubuntu:24.04:LTS: ruby-rack, Ubuntu:25.10: ruby-rack, Ubuntu:26.04:LTS: ruby-rack

Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Multipart::Parser only wraps the request body in a BoundedIO when CONTENT_LENGTH is present. When a multipart/form-data request is sent without a Content-Length header, such as with HTTP chunked transfer encoding, multipart parsing continues until end-of-stream with no total size limit. For file parts, the uploaded body is written directly to a temporary file on disk rather than being constrained by the buffered in-memory upload limit. An unauthenticated attacker can therefore stream an arbitrarily large multipart file upload and consume unbounded disk space. This results in a denial of service condition for Rack applications that accept multipart form data. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.

Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in IBM License Metric Tool ausnutzen, um einen nicht näher spezifizierten Angriff durchzuführen.