# CVE-2025-59830: Rack has an unsafe default in Rack::QueryParser allows params_limit bypass via semicolon-separated parameters

Source: https://junglewise.ai/threats/cve-2025-59830-rack-has-an-unsafe-default-in-rack-queryparser-allows-params  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2025-09-25  
License: CC BY 4.0 with a link back

CVE-2025-59830 · Severity: low · CVSS 3.1 · Published 2025-09-25

Rack has an unsafe default in Rack::QueryParser allows params_limit bypass via semicolon-separated parameters

Technologies: [rack (RubyGems)](https://junglewise.ai/threats/technologies/rack). Vendors: [RubyGems](https://junglewise.ai/threats/vendors/rubygems).

## Quick answers

**Is CVE-2025-59830 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2025-59830 being exploited in the wild.

**How severe is CVE-2025-59830?** Low severity, with a CVSS score of 3.1, published 25 September 2025.

**Which products and versions are affected?** rack (RubyGems) ECOSYSTEM:introduced=0,fixed=2.2.18.

**Is there a fix for CVE-2025-59830?** Yes. rack (RubyGems): upgrade to 2.2.18 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2025-59830?** Check whether you run rack (RubyGems) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- rack (RubyGems): upgrade to 2.2.18 or later

  ```sh
  bundle update rack
  ```


## Affected products

- rack (RubyGems) ECOSYSTEM:introduced=0,fixed=2.2.18

## Identifiers

- CVE-2025-59830
- GHSA-625h-95r8-8xpm

## Related threats

- [Rack multipart parser denial of service via unbounded scan buffer growth](https://junglewise.ai/threats/cve-2026-125111-rack-multipart-parsing-allows-dos-via-unbounded-scan-buffer)
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- [Rack host validation bypass via HTTP headers](https://junglewise.ai/threats/cve-2026-125109-rack-is-a-modular-ruby-web-server-interface-from-3-0-until-3-1)
- [Rack is a modular Ruby web server interface. Prior to 2.2.25, 3.1.23, and 3.2.8…](https://junglewise.ai/threats/cve-2026-125108-rack-multipart-boundary-ambiguity-guard-in-rack-multipart-parser)
- [Rack Rack::Request host allowlist bypass via Host header poisoning](https://junglewise.ai/threats/cve-2026-34835-rack-rack-request-host-allowlist-bypass-via-host-header-poisoning)