CVE-2025-27220
CGI has Regular Expression Denial of Service (ReDoS) potential in Util#escapeElement
Impact
There is a possibility for Regular expression Denial of Service (ReDoS) by in the cgi gem. This vulnerability has been assigned the CVE identifier CVE-2025-27220. We recommend upgrading the cgi gem. ## Details The regular expression used in `CGI::Util#escapeElement` is vulnerable to ReDoS. The crafted input could lead to a high CPU consumption. This vulnerability only affects Ruby 3.1 and 3.2. If you are using these versions, please update CGI gem to version 0.3.5.1, 0.3.7, 0.4.2 or later. ## Affected versions cgi gem versions <= 0.3.5, 0.3.6, 0.4.0 and 0.4.1. ## Credits Thanks to svalkanov for discovering this issue. Also thanks to nobu for fixing this vulnerability.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| rubygems | cgi | < 0.3.5.1 | 0.3.5.1 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Ruby-Lang | Cgi | before 0.3.5.1 from 0.4.0 before 0.4.2 Version 0.3.6 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/rubysec/ruby-advisory-db/blob/master/gems/cgi/CVE-2025-27220.yml
- https://hackerone.com/reports/2890322
- https://lists.debian.org/debian-lts-announce/2025/03/msg00008.html
- https://github.com/advisories/GHSA-mhwm-jh88-3gjf
- https://github.com/ruby/cgi/pull/52
- https://github.com/ruby/cgi/pull/53
- https://github.com/ruby/cgi/pull/54
- https://www.cve.org/CVERecord?id=CVE-2025-27220
- https://www.ruby-lang.org/en/news/2025/02/26/security-advisories
- https://nvd.nist.gov/vuln/detail/CVE-2025-27220