Cgi vulnerabilitiesRanked by how likely they are to be used.
Cgi is made by Ruby-Lang. We track 5 published vulnerabilities in it, across 12 versions. None of them is on the list of flaws known to be exploited today. If you run Cgi, keep it on a version the vendor still supports.
We keep watching the known-exploited list.
Which Cgi vulnerabilities are being exploited?
This is the list that matters most: flaws criminals are using now.
None of Cgi's published vulnerabilities is on the list of flaws known to be exploited today. We keep watching that list.
Which Cgi flaws are most likely to be used?
Ranked by the latest exploit-likelihood forecast: the chance each flaw is used in an attack in the next 30 days. A high severity score on its own doesn't tell you that. Flaws shared by many other makers' products are left out.
- 4.9%CVE-2021-41816Critical
CGI.escape_html in Ruby before 2.7.5 and 3.x before 3.0.3 has an integer overflow and resultant buffer overflow via a long string on platforms (such as Windows) where size_t and long have different numbers of bytes.
- 2.9%CVE-2021-41819High
CGI::Cookie.parse in Ruby through 2.6.8 mishandles security prefixes in cookie names.
- 2.4%CVE-2021-33621High
The cgi gem before 0.1.0.2, 0.2.x before 0.2.2, and 0.3.x before 0.3.5 for Ruby allows HTTP response splitting.
- 0.8%CVE-2025-27219Medium
In the CGI gem before 0.4.2 for Ruby, the CGI::Cookie.parse method in the CGI library contains a potential Denial of Service (DoS) vulnerability.
- 0.8%CVE-2025-27220Medium
In the CGI gem before 0.4.2 for Ruby, a Regular Expression Denial of Service (ReDoS) vulnerability exists in the Util#escapeElement method.
Running Cgi? We'll keep checking.
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1 new flaw affects software Acme tracks
CGI.escape_html in Ruby before 2.7.5 and 3.x before 3.0.3 has an integer overflow and resultant buffer overflow via a long string on platforms (such as Windows) where size_t and long have different numbers of bytes. This also affects the CGI gem before 0.3.1 for Ruby.
- Matched to
- Cgi on Acme's software list
- What to do
- Plan in the vendor’s update
Sent to the alert recipients Acme chose. Also in the app and to Acme's webhook.
We track 5 published vulnerabilities listed under the name Cgi, across 12 versions.
None of Cgi's vulnerabilities is on the list of flaws known to be exploited today.
Create a Precursor Intelligence account and track Cgi. We match it against every published flaw, give each one a risk score from 0 to 100 and keep watching, so you hear about new ones as soon as we know, by email, in the app or by webhook.