Regular Expression Denial of Service in Ruby's CGI Gem
CVE-2025-27220

7.5HIGH

Key Information:

Vendor

Ruby-lang

Status
Cgi
Vendor
CVE Published:
4 March 2025

What is CVE-2025-27220?

A Regular Expression Denial of Service (ReDoS) vulnerability is present in the Util#escapeElement method within the CGI gem for Ruby versions prior to 0.4.2. This flaw can be exploited by an attacker to cause significant delays in processing requests, potentially leading to degraded service and application unavailability. The vulnerability arises from insufficiently optimized regular expressions that can be manipulated to consume extensive resources when processing certain inputs.

Affected Version(s)

CGI 0 < 0.3.5.1

CGI 0.3.6 < 0.3.7

CGI 0.4.0 < 0.4.2

References

https://hackerone.com/reports/2890322
https://github.com/rubysec/ruby-advisory-db/blob/master/g...

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

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