8.8
HIGH
CVE-2021-33621
Apache CGI HTTP Response Splitting
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.

INFO

Published Date :

Nov. 18, 2022, 11:15 p.m.

Last Modified :

Nov. 21, 2024, 6:09 a.m.

Source :

[email protected]

Remotely Exploitable :

Yes !

Impact Score :

5.9

Exploitability Score :

2.8
Affected Products

The following products are affected by CVE-2021-33621 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Ruby-lang ruby
2 Ruby-lang cgi
1 Fedoraproject fedora
: Total Affected Vendor : 2 | Products : 3
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2021-33621.

URL Resource
https://lists.debian.org/debian-lts-announce/2023/06/msg00012.html
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/THVTYHHEOVLQFCFHWURZYO7PVUPBHRZD/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YACE6ORF2QBXXBK2V2CM36D7TZMEJVAS/
https://security.gentoo.org/glsa/202401-27
https://security.netapp.com/advisory/ntap-20221228-0004/ Third Party Advisory
https://www.ruby-lang.org/en/news/2022/11/22/http-response-splitting-in-cgi-cve-2021-33621/ Exploit Third Party Advisory
https://lists.debian.org/debian-lts-announce/2023/06/msg00012.html
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/THVTYHHEOVLQFCFHWURZYO7PVUPBHRZD/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YACE6ORF2QBXXBK2V2CM36D7TZMEJVAS/
https://security.gentoo.org/glsa/202401-27
https://security.netapp.com/advisory/ntap-20221228-0004/ Third Party Advisory
https://www.ruby-lang.org/en/news/2022/11/22/http-response-splitting-in-cgi-cve-2021-33621/ Exploit Third Party Advisory

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2021-33621 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2021-33621 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by af854a3a-2127-422b-91ae-364da2661108

    Nov. 21, 2024

    Action Type Old Value New Value
    Added Reference https://lists.debian.org/debian-lts-announce/2023/06/msg00012.html
    Added Reference https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DQR7LWED6VAPD5ATYOBZIGJQPCUBRJBX/
    Added Reference https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/THVTYHHEOVLQFCFHWURZYO7PVUPBHRZD/
    Added Reference https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YACE6ORF2QBXXBK2V2CM36D7TZMEJVAS/
    Added Reference https://security.gentoo.org/glsa/202401-27
    Added Reference https://security.netapp.com/advisory/ntap-20221228-0004/
    Added Reference https://www.ruby-lang.org/en/news/2022/11/22/http-response-splitting-in-cgi-cve-2021-33621/
  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • CVE Modified by [email protected]

    Jan. 24, 2024

    Action Type Old Value New Value
    Added Reference MITRE https://security.gentoo.org/glsa/202401-27 [No types assigned]
  • CVE Modified by [email protected]

    Nov. 07, 2023

    Action Type Old Value New Value
    Added Reference MITRE https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DQR7LWED6VAPD5ATYOBZIGJQPCUBRJBX/ [No types assigned]
    Added Reference MITRE https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YACE6ORF2QBXXBK2V2CM36D7TZMEJVAS/ [No types assigned]
    Added Reference MITRE https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/THVTYHHEOVLQFCFHWURZYO7PVUPBHRZD/ [No types assigned]
    Removed Reference MITRE https://lists.fedoraproject.org/archives/list/[email protected]/message/YACE6ORF2QBXXBK2V2CM36D7TZMEJVAS/
    Removed Reference MITRE https://lists.fedoraproject.org/archives/list/[email protected]/message/DQR7LWED6VAPD5ATYOBZIGJQPCUBRJBX/
    Removed Reference MITRE https://lists.fedoraproject.org/archives/list/[email protected]/message/THVTYHHEOVLQFCFHWURZYO7PVUPBHRZD/
  • CWE Remap by [email protected]

    Aug. 08, 2023

    Action Type Old Value New Value
    Changed CWE CWE-436 CWE-74
  • CVE Modified by [email protected]

    Jun. 09, 2023

    Action Type Old Value New Value
    Added Reference https://lists.debian.org/debian-lts-announce/2023/06/msg00012.html [No Types Assigned]
  • Reanalysis by [email protected]

    May. 16, 2023

    Action Type Old Value New Value
    Added CPE Configuration OR *cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:* versions from (including) 2.7.0 up to (excluding) 2.7.7 *cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:* versions from (including) 3.0.0 up to (excluding) 3.0.5 *cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:* versions from (including) 3.1.0 up to (excluding) 3.1.3
  • Modified Analysis by [email protected]

    Jan. 12, 2023

    Action Type Old Value New Value
    Changed Reference Type https://lists.fedoraproject.org/archives/list/[email protected]/message/DQR7LWED6VAPD5ATYOBZIGJQPCUBRJBX/ No Types Assigned https://lists.fedoraproject.org/archives/list/[email protected]/message/DQR7LWED6VAPD5ATYOBZIGJQPCUBRJBX/ Mailing List, Third Party Advisory
    Changed Reference Type https://lists.fedoraproject.org/archives/list/[email protected]/message/THVTYHHEOVLQFCFHWURZYO7PVUPBHRZD/ No Types Assigned https://lists.fedoraproject.org/archives/list/[email protected]/message/THVTYHHEOVLQFCFHWURZYO7PVUPBHRZD/ Mailing List, Third Party Advisory
    Changed Reference Type https://lists.fedoraproject.org/archives/list/[email protected]/message/YACE6ORF2QBXXBK2V2CM36D7TZMEJVAS/ No Types Assigned https://lists.fedoraproject.org/archives/list/[email protected]/message/YACE6ORF2QBXXBK2V2CM36D7TZMEJVAS/ Mailing List, Third Party Advisory
    Changed Reference Type https://security.netapp.com/advisory/ntap-20221228-0004/ No Types Assigned https://security.netapp.com/advisory/ntap-20221228-0004/ Third Party Advisory
    Added CPE Configuration OR *cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:* *cpe:2.3:o:fedoraproject:fedora:36:*:*:*:*:*:*:* *cpe:2.3:o:fedoraproject:fedora:37:*:*:*:*:*:*:*
  • CVE Modified by [email protected]

    Dec. 28, 2022

    Action Type Old Value New Value
    Added Reference https://security.netapp.com/advisory/ntap-20221228-0004/ [No Types Assigned]
  • CVE Modified by [email protected]

    Dec. 09, 2022

    Action Type Old Value New Value
    Added Reference https://lists.fedoraproject.org/archives/list/[email protected]/message/THVTYHHEOVLQFCFHWURZYO7PVUPBHRZD/ [No Types Assigned]
  • CVE Modified by [email protected]

    Dec. 08, 2022

    Action Type Old Value New Value
    Added Reference https://lists.fedoraproject.org/archives/list/[email protected]/message/YACE6ORF2QBXXBK2V2CM36D7TZMEJVAS/ [No Types Assigned]
    Added Reference https://lists.fedoraproject.org/archives/list/[email protected]/message/DQR7LWED6VAPD5ATYOBZIGJQPCUBRJBX/ [No Types Assigned]
  • Initial Analysis by [email protected]

    Nov. 22, 2022

    Action Type Old Value New Value
    Added CVSS V3.1 NIST AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
    Changed Reference Type https://www.ruby-lang.org/en/news/2022/11/22/http-response-splitting-in-cgi-cve-2021-33621/ No Types Assigned https://www.ruby-lang.org/en/news/2022/11/22/http-response-splitting-in-cgi-cve-2021-33621/ Exploit, Third Party Advisory
    Added CWE NIST CWE-436
    Added CPE Configuration OR *cpe:2.3:a:ruby-lang:cgi:*:*:*:*:*:ruby:*:* versions up to (excluding) 0.1.0.2 *cpe:2.3:a:ruby-lang:cgi:*:*:*:*:*:ruby:*:* versions from (including) 0.2.0 up to (excluding) 0.2.2 *cpe:2.3:a:ruby-lang:cgi:*:*:*:*:*:ruby:*:* versions from (including) 0.3.0 up to (excluding) 0.3.5
  • CVE Modified by [email protected]

    Nov. 22, 2022

    Action Type Old Value New Value
    Changed Description ** REJECT ** DO NOT USE THIS CANDIDATE NUMBER. ConsultIDs: none. Reason: This candidate was withdrawn by its CNA. Further investigation showed that it was not a security issue. Notes: none. 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.
    Added Reference https://www.ruby-lang.org/en/news/2022/11/22/http-response-splitting-in-cgi-cve-2021-33621/ [No Types Assigned]
  • CVE Unrejected by [email protected]

    Nov. 22, 2022

    Action Type Old Value New Value
  • CVE Modified by [email protected]

    Nov. 19, 2022

    Action Type Old Value New Value
    Changed Description cgi.rb in Ruby through 2.6.x, through 3.0x, and through 3.1.x allows HTTP header injection. If a CGI application using the CGI library inserts untrusted input into the HTTP response header, an attacker can exploit it to insert a newline character to split a header, and inject malicious content to deceive clients. ** REJECT ** DO NOT USE THIS CANDIDATE NUMBER. ConsultIDs: none. Reason: This candidate was withdrawn by its CNA. Further investigation showed that it was not a security issue. Notes: none.
    Removed Reference https://hackerone.com/reports/1204695 [No Types Assigned]
  • CVE Rejected by [email protected]

    Nov. 19, 2022

    Action Type Old Value New Value
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2021-33621 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2021-33621 weaknesses.

CAPEC-3: Using Leading 'Ghost' Character Sequences to Bypass Input Filters Using Leading 'Ghost' Character Sequences to Bypass Input Filters CAPEC-6: Argument Injection Argument Injection CAPEC-7: Blind SQL Injection Blind SQL Injection CAPEC-8: Buffer Overflow in an API Call Buffer Overflow in an API Call CAPEC-9: Buffer Overflow in Local Command-Line Utilities Buffer Overflow in Local Command-Line Utilities CAPEC-10: Buffer Overflow via Environment Variables Buffer Overflow via Environment Variables CAPEC-13: Subverting Environment Variable Values Subverting Environment Variable Values CAPEC-14: Client-side Injection-induced Buffer Overflow Client-side Injection-induced Buffer Overflow CAPEC-24: Filter Failure through Buffer Overflow Filter Failure through Buffer Overflow CAPEC-28: Fuzzing Fuzzing CAPEC-34: HTTP Response Splitting HTTP Response Splitting CAPEC-42: MIME Conversion MIME Conversion CAPEC-43: Exploiting Multiple Input Interpretation Layers Exploiting Multiple Input Interpretation Layers CAPEC-45: Buffer Overflow via Symbolic Links Buffer Overflow via Symbolic Links CAPEC-46: Overflow Variables and Tags Overflow Variables and Tags CAPEC-47: Buffer Overflow via Parameter Expansion Buffer Overflow via Parameter Expansion CAPEC-51: Poison Web Service Registry Poison Web Service Registry CAPEC-52: Embedding NULL Bytes Embedding NULL Bytes CAPEC-53: Postfix, Null Terminate, and Backslash Postfix, Null Terminate, and Backslash CAPEC-64: Using Slashes and URL Encoding Combined to Bypass Validation Logic Using Slashes and URL Encoding Combined to Bypass Validation Logic CAPEC-67: String Format Overflow in syslog() String Format Overflow in syslog() CAPEC-71: Using Unicode Encoding to Bypass Validation Logic Using Unicode Encoding to Bypass Validation Logic CAPEC-72: URL Encoding URL Encoding CAPEC-76: Manipulating Web Input to File System Calls Manipulating Web Input to File System Calls CAPEC-78: Using Escaped Slashes in Alternate Encoding Using Escaped Slashes in Alternate Encoding CAPEC-79: Using Slashes in Alternate Encoding Using Slashes in Alternate Encoding CAPEC-80: Using UTF-8 Encoding to Bypass Validation Logic Using UTF-8 Encoding to Bypass Validation Logic CAPEC-83: XPath Injection XPath Injection CAPEC-84: XQuery Injection XQuery Injection CAPEC-101: Server Side Include (SSI) Injection Server Side Include (SSI) Injection CAPEC-105: HTTP Request Splitting HTTP Request Splitting CAPEC-108: Command Line Execution through SQL Injection Command Line Execution through SQL Injection CAPEC-120: Double Encoding Double Encoding CAPEC-135: Format String Injection Format String Injection CAPEC-250: XML Injection XML Injection CAPEC-267: Leverage Alternate Encoding Leverage Alternate Encoding CAPEC-273: HTTP Response Smuggling HTTP Response Smuggling
Exploit Prediction

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.

0.65 }} 0.13%

score

0.79257

percentile

CVSS31 - Vulnerability Scoring System
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability
: