GHSA-mhwm-jh88-3gjf
CGI has Regular Expression Denial of Service (ReDoS) potential in Util#escapeElement
Quick fix
GHSA-mhwm-jh88-3gjf — cgi: upgrade to the fixed version with the command below.
bundle update cgiDetails
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.
Are you affected?
Enter the version of the package you're using.
Affected packages
References
- https://nvd.nist.gov/vuln/detail/CVE-2025-27220[ADVISORY]
- https://github.com/ruby/cgi/pull/52[WEB]
- https://github.com/ruby/cgi/pull/53[WEB]
- https://github.com/ruby/cgi/pull/54[WEB]
- https://hackerone.com/reports/2890322[WEB]
- https://github.com/ruby/cgi[PACKAGE]
- https://github.com/rubysec/ruby-advisory-db/blob/master/gems/cgi/CVE-2025-27220.yml[WEB]
- https://lists.debian.org/debian-lts-announce/2025/03/msg00008.html[WEB]
- https://www.cve.org/CVERecord?id=CVE-2025-27220[WEB]
- https://www.ruby-lang.org/en/news/2025/02/26/security-advisories[WEB]