Denial of Service Vulnerability in Rack Modular Web Server Interface by Rack
CVE-2025-59830

7.5HIGH

Key Information:

Vendor

Rack

Status
Rack
Vendor
CVE Published:
25 September 2025

What is CVE-2025-59830?

The Rack modular web server interface has a vulnerability in its QueryParser component, where the params_limit is enforced only for parameters separated by '&' but not by ';'. This flaw allows attackers to use ';' as a separator, enabling the submission of more parameters than intended, leading to potential resource exhaustion. Applications or middleware invoking Rack::QueryParser with default settings may face increased CPU and memory consumption, which could serve as a vector for a denial-of-service attack. This issue has been addressed in version 2.2.18.

Affected Version(s)

rack < 2.2.18

References

https://github.com/rack/rack/security/advisories/GHSA-625...
x_refsource_CONFIRM
https://github.com/rack/rack/commit/54e4ffdd5affebcb0c015...
x_refsource_MISC

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

JSON
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CVE-2025-59830 : Denial of Service Vulnerability in Rack Modular Web Server Interface by Rack