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…
Priority MEDIUM 43CWE-74Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 7 fixed, 3 without a fix
Attack profile from CVSS 3.1 · NVD. Fix status from CNA, GitHub and Red Hat.
Summary
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.
Why it matters now
EPSS 0.02452 84th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Partial cgi (RubyGems): 0.3.5, 0.2.2, 0.1.0.2Red Hat: 8 advisoriesRed Hat: 7 fixed, 3 without a fix
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
| — | cgi (RubyGems) | 0.3.0 to before 0.3.5 | 0.3.5 | Patch available | GHSA-vc47-6rqg-c7f5 |
| — | cgi (RubyGems) | 0.2.0 to before 0.2.2 | 0.2.2 | Patch available | GHSA-vc47-6rqg-c7f5 |
| — | cgi (RubyGems) | before 0.1.0.2 | 0.1.0.2 | Patch available | GHSA-vc47-6rqg-c7f5 |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
- cgi (RubyGems) Vendor— Affected 0.3.0 to before 0.3.5 Fixed in 0.3.5 Patch available GHSA-vc47-6rqg-c7f5
- cgi (RubyGems) Vendor— Affected 0.2.0 to before 0.2.2 Fixed in 0.2.2 Patch available GHSA-vc47-6rqg-c7f5
- cgi (RubyGems) Vendor— Affected before 0.1.0.2 Fixed in 0.1.0.2 Patch available GHSA-vc47-6rqg-c7f5
CPE configurations NVD · 5
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:ruby-lang:cgi:*:*:*:*:*:ruby:*:* | before 0.1.0.2; 0.2.0 to before 0.2.2; 0.3.0 to before 0.3.5 | Vulnerable | ruby |
| cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:* | 35 | Vulnerable | Fedoraproject |
| cpe:2.3:o:fedoraproject:fedora:36:*:*:*:*:*:*:* | 36 | Vulnerable | Fedoraproject |
| cpe:2.3:o:fedoraproject:fedora:37:*:*:*:*:*:*:* | 37 | Vulnerable | Fedoraproject |
| cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:* | 2.7.0 to before 2.7.7; 3.0.0 to before 3.0.5; 3.1.0 to before 3.1.3 | Vulnerable | ruby |
- cpe:2.3:a:ruby-lang:cgi:*:*:*:*:*:ruby:*:* Versions before 0.1.0.2; 0.2.0 to before 0.2.2; 0.3.0 to before 0.3.5 Vulnerable ·ruby
- cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:* Versions 35 Vulnerable ·Fedoraproject
- cpe:2.3:o:fedoraproject:fedora:36:*:*:*:*:*:*:* Versions 36 Vulnerable ·Fedoraproject
- cpe:2.3:o:fedoraproject:fedora:37:*:*:*:*:*:*:* Versions 37 Vulnerable ·Fedoraproject
- cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:* Versions 2.7.0 to before 2.7.7; 3.0.0 to before 3.0.5; 3.1.0 to before 3.1.3 Vulnerable ·ruby
Remediation
- Fix · GHSA-vc47-6rqg-c7f5 cgi (RubyGems) Fixed in 0.3.5 Advisory →
- Fix · GHSA-vc47-6rqg-c7f5 cgi (RubyGems) Fixed in 0.2.2 Advisory →
- Fix · GHSA-vc47-6rqg-c7f5 cgi (RubyGems) Fixed in 0.1.0.2 Advisory →
Red Hat 8 advisories
- RHSA-2024:4542 Released 2024-07-15 · Red Hat rating Moderateruby security update
- Red Hat CodeReady Linux Builder EUS (v.9.2) ruby-doc-3.0.4-161.el9_2.1
- Red Hat Enterprise Linux AppStream EUS (v.9.2) ruby-3.0.4-161.el9_2.1, ruby-default-gems-3.0.4-161.el9_2.1, ruby-devel-3.0.4-161.el9_2.1 +18
- RHSA-2024:3838 Released 2024-06-11 · Red Hat rating Moderateruby security update
- Red Hat Enterprise Linux AppStream (v. 9) ruby-3.0.7-162.el9_4, ruby-default-gems-3.0.7-162.el9_4, ruby-devel-3.0.7-162.el9_4 +18
- Red Hat Enterprise Linux CRB (v. 9) ruby-doc-3.0.7-162.el9_4
- RHSA-2024:3500 Released 2024-05-30 · Red Hat rating Moderateruby:3.0 security update
- Red Hat Enterprise Linux AppStream (v. 8) ruby-3.0.7-143.module+el8.10.0+21858+d19f3934.aarch64::ruby:3.0, ruby-3.0.7-143.module+el8.10.0+21858+d19f3934.i686::ruby:3.0, ruby-3.0.7-143.module+el8.10.0+21858+d19f3934.ppc64le::ruby:3.0 +47
Show 5 more Red Hat advisories
- RHSA-2024:1576 Released 2024-04-01 · Red Hat rating Moderateruby:3.1 security, bug fix, and enhancement update
- Red Hat Enterprise Linux AppStream (v. 9) ruby-3.1.4-143.module+el9.3.0+21558+96b51efd.aarch64::ruby:3.1, ruby-3.1.4-143.module+el9.3.0+21558+96b51efd.i686::ruby:3.1, ruby-3.1.4-143.module+el9.3.0+21558+96b51efd.ppc64le::ruby:3.1 +47
- RHSA-2024:1431 Released 2024-03-19 · Red Hat rating Moderateruby:3.1 security, bug fix, and enhancement update
- Red Hat Enterprise Linux AppStream (v. 8) ruby-3.1.4-142.module+el8.9.0+21471+7d1e4a35.aarch64::ruby:3.1, ruby-3.1.4-142.module+el8.9.0+21471+7d1e4a35.i686::ruby:3.1, ruby-3.1.4-142.module+el8.9.0+21471+7d1e4a35.ppc64le::ruby:3.1 +47
- RHSA-2023:7025 Released 2023-11-14 · Red Hat rating Moderateruby:2.5 security update
- Red Hat Enterprise Linux AppStream (v. 8) ruby-2.5.9-111.module+el8.9.0+19193+435404ae.aarch64::ruby:2.5, ruby-2.5.9-111.module+el8.9.0+19193+435404ae.i686::ruby:2.5, ruby-2.5.9-111.module+el8.9.0+19193+435404ae.ppc64le::ruby:2.5 +47
- RHSA-2023:3821 Released 2023-06-27 · Red Hat rating Moderateruby:2.7 security, bug fix, and enhancement update
- Red Hat Enterprise Linux AppStream (v. 8) ruby-2.7.8-139.module+el8.8.0+18745+f1bef313.aarch64::ruby:2.7, ruby-2.7.8-139.module+el8.8.0+18745+f1bef313.i686::ruby:2.7, ruby-2.7.8-139.module+el8.8.0+18745+f1bef313.ppc64le::ruby:2.7 +47
- RHSA-2023:3291 Released 2023-05-24 · Red Hat rating Moderaterh-ruby27-ruby security, bug fix, and enhancement update
- Red Hat Software Collections for RHEL Workstation(v. 7) rh-ruby27-ruby-2.7.8-132.el7, rh-ruby27-ruby-devel-2.7.8-132.el7, rh-ruby27-ruby-doc-2.7.8-132.el7 +19
- Red Hat Software Collections for RHEL(v. 7) rh-ruby27-ruby-2.7.8-132.el7, rh-ruby27-ruby-devel-2.7.8-132.el7, rh-ruby27-ruby-doc-2.7.8-132.el7 +19
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix planned: Out of support scope |
| Red Hat Software Collections | Affected | No fix planned: Will not fix |
| Red Hat CodeReady Linux Builder EUS (v.9.2) | Fixed | RHSA-2024:4542 |
| Red Hat Enterprise Linux AppStream (v. 8) | Fixed | RHSA-2023:3821, RHSA-2023:7025, RHSA-2024:1431, RHSA-2024:3500 |
| Red Hat Enterprise Linux AppStream (v. 9) | Fixed | RHSA-2024:1576, RHSA-2024:3838 |
| Red Hat Enterprise Linux AppStream EUS (v.9.2) | Fixed | RHSA-2024:4542 |
| Red Hat Enterprise Linux CRB (v. 9) | Fixed | RHSA-2024:3838 |
| Red Hat Software Collections for RHEL Workstation(v. 7) | Fixed | RHSA-2023:3291 |
| Red Hat Software Collections for RHEL(v. 7) | Fixed | RHSA-2023:3291 |
Timeline
- 2026-10-02 Threatist record created from CVE-2021-33621
- 2026-10-03 Alias added: GHSA-vc47-6rqg-c7f5
References
Exploit 1
Advisory 6
Other 12
- [debian-lts-announce] 20230609 [SECURITY] [DLA 3450-1] ruby2.5 security update
- https://hackerone.com/reports/1204695
- https://github.com/rubysec/ruby-advisory-db/blob/master/gems/cgi/CVE-2021-33621.yml
- https://lists.debian.org/debian-lts-announce/2024/09/msg00000.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://lists.fedoraproject.org/archives/list/[email protected]/message/DQR7LWED6VAPD5ATYOBZIGJQPCUBRJBX
- https://lists.fedoraproject.org/archives/list/[email protected]/message/THVTYHHEOVLQFCFHWURZYO7PVUPBHRZD
- https://lists.fedoraproject.org/archives/list/[email protected]/message/YACE6ORF2QBXXBK2V2CM36D7TZMEJVAS
- https://security.netapp.com/advisory/ntap-20221228-0004
- https://www.ruby-lang.org/en/news/2022/11/22/http-response-splitting-in-cgi-cve-2021-33621
Sources
- CVE-2021-33621 · CVE Program
- CVE-2021-33621 · NVD
- FIRST EPSS
- GHSA-vc47-6rqg-c7f5 · GitHub Advisory Database · CC BY 4.0
- CVE-2021-33621 · Red Hat security data · CC BY 4.0
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