GHSA-jqx4-9gpq-rppm @misskey-dev/summaly allows IP Filter Bypass via Redirect

• npm @misskey-dev/summaly: >= 5.1.0, < 5.2.1 → fixed in 5.2.1

Summary Due to a validation error in `got.scpaping`, it is possible to use an HTTP redirect to avoid IP filtering. Details In `got.scpaping`, Summaly first makes a HTTP `HEAD` request to the page being summarized. It then preforms private IP address checks on the `HEAD` response, then makes an additional HTTP `GET` request to the page being summarized. Unfortunately, since private IP address checks aren't performed on the `GET` response, the `GET` response can issue a HTTP redirect to a private IP address, which will succeed, regardless of if private IP addresses are allowed by Summaly. PoC With a simple Caddy webserver, you can get Summaly to summarize a page hosted via a local IP address: ```caddy @summaly-bypass-head { method HEAD path /summaly-bypass } @summaly-bypass-get { method GET path /summaly-bypass } header @summaly-bypass-head Content-Type "text/html" respond @summaly-bypass-head 200 redir @summaly-bypass-get http://127.0.0.1:3080/ ``` Impact Using this bypass, an attacker can probe a victims internal network for HTTP services that aren't supposed to be exposed to the outside world. While they might only have read-only access through this, it may still be possible to extract sensitive information or be used to probe a network prior to attacking via other exploits without leaving a trace.