Back to Database
Status published
High
CVE-2021-33621
The cgi gem before 0.1.0.2, 0.2.x before 0.2.2, and 0.3.x...
Vulnerability Description
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. This is relevant to applications that use untrusted user input either to generate an HTTP response or to create a CGI::Cookie object.
Impact Analysis
Refer to official advisory for detailed impact metrics.
Remediation
Ensure systems are updated to the latest vendor-supplied patch levels.
THREAT MONITOR
Am I Vulnerable?
Launch our assessment wizard to check if your infrastructure is exposed to • CVE-2021-33621
Credits & Attribution
No credits recorded in the NVD database.
References
- https://www.ruby-lang.org/en/news/2022/11/22/http-response-splitting-in-cgi-cve-2021-33621/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DQR7LWED6VAPD5ATYOBZIGJQPCUBRJBX/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YACE6ORF2QBXXBK2V2CM36D7TZMEJVAS/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/THVTYHHEOVLQFCFHWURZYO7PVUPBHRZD/
- https://security.netapp.com/advisory/ntap-20221228-0004/
- https://lists.debian.org/debian-lts-announce/2023/06/msg00012.html
- https://security.gentoo.org/glsa/202401-27
More from ruby-lang
View All →CVE-2025-27221
In the URI gem before 1.0.3 for Ruby, the URI...
Low
3.2
CVE-2025-27220
In the CGI gem before 0.4.2 for Ruby, a Regular...
Medium
4
CVE-2025-27219
In the CGI gem before 0.4.2 for Ruby, the CGI::Cookie.parse...
Medium
5.8
CVE-2022-28739
There is a buffer over-read in Ruby before 2.6.10, 2.7.x...
High
7.5
CVE-2022-28738
A double free was found in the Regexp compiler in...
Critical
9.8
Affected Vendor
ruby-lang
View all reports →Affected Software
cgi, fedora, ruby
Vulnerable Versions:
0, 0.2.0, 0.3.0, 35, 36, 37, 2.7.0, 3.0.0, 3.1.0
Timeline
Official Publish:
November 18th, 2022
Last Modified:
November 4th, 2025
Added to House:
July 21st, 2026
CVSS Vectors
V3:
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weaknesses (CWE)
No CWE data available
MITRE ATT&CK TTPs
No associated TTPs found for this vulnerability.