PT-2025-20008 · Npm · @Misskey-Dev/Summaly

Published

2025-05-06

·

Updated

2025-05-06

CVSS v3.1

5.3

Medium

VectorAV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

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.

Fix

Origin Validation Error

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Weakness Enumeration

Related Identifiers

GHSA-JQX4-9GPQ-RPPM

Affected Products

@Misskey-Dev/Summaly