CVE-2025-27220
MEDIUM4.0EPSS 0.25%CGI has Regular Expression Denial of Service (ReDoS) potential in Util#escapeElement
Description
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 (4)
- Debian/ruby2.7from 0, < 2.7.4-1+deb11u5
- Debian/ruby3.1from 0
- Debian/ruby3.3from 0, < 3.3.7-2
- RubyGems/cgifrom 0, < 0.3.5.1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N |
| osv | CVSS 3.1 | MEDIUM4.0 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:L |
References (11)
- ADVISORYhttps://nvd.nist.gov/vuln/detail/CVE-2025-27220
- ADVISORYhttps://security-tracker.debian.org/tracker/CVE-2025-27220
- PATCHhttps://github.com/ruby/cgi
- WEBhttps://github.com/ruby/cgi/pull/52
- WEBhttps://github.com/ruby/cgi/pull/53
- WEBhttps://github.com/ruby/cgi/pull/54
- WEBhttps://github.com/rubysec/ruby-advisory-db/blob/master/gems/cgi/CVE-2025-27220.yml
- WEBhttps://hackerone.com/reports/2890322
- WEBhttps://lists.debian.org/debian-lts-announce/2025/03/msg00008.html
- WEBhttps://www.cve.org/CVERecord?id=CVE-2025-27220
- WEBhttps://www.ruby-lang.org/en/news/2025/02/26/security-advisories