| C-3.co.jp | 1 | 2 |
| C-DATA | 1 | 2 |
| C-MORE | 1 | 5 |
| C-ares | 1 | 9 |
| C-ares Project | 1 | 9 |
| C-blosc2 Project | 1 | 5 |
| C-board Moyuku Project | 1 | 2 |
| C-data Onu4ferw Project | 1 | 1 |
| C-http Project | 1 | 1 |
| C-icap Project | 1 | 2 |
| C-news.fr | 1 | 3 |
| C-note | 1 | 1 |
| C-sam | 1 | 1 |
| C.p.sub Project | 1 | 2 |
| C2FO | 1 | 1 |
| C2ae | 1 | 1 |
| C2enterprise | 1 | 1 |
| C2fo | 1 | 1 |
| C2net | 1 | 1 |
| C3-ilex | 1 | 4 |
| C3 Token Project | 1 | 1 |
| C4b | 1 | 1 |
| C61 | 1 | 1 |
| C97 | 1 | 3 |
| C97net | 1 | 7 |
| CA Technologies | 12 | 55 |
| CA Technologies - A Broadcom Company | 2 | 4 |
| CA Technologies, A Broadcom Company | 5 | 7 |
| CA Technologies, Broadcom Company | 1 | 1 |
| CA Technologies, A Broadcom Company | 1 | 1 |
| CAGE Web Design | Rolf Van Gelder | 1 | 1 |
| CBC Co.,Ltd. | 5 | 15 |
| CBOT | 1 | 6 |
| CELSYS, Inc. | 1 | 1 |
| CERN | 1 | 2 |
| CERT/CC | 1 | 4 |
| CESNET | 2 | 2 |
| CF Software | 1 | 1 |
| CFME | 1 | 3 |
| CFME (CloudForms Management Engine) | 1 | 1 |
| CGAL Project | 1 | 38 |
| CGI Script Market | 1 | 1 |
| CHANGING | 2 | 6 |
| CHANGING Inc. | 2 | 6 |
| CIRCUTOR | 1 | 1 |
| CImg | 1 | 1 |
| CKSource | 2 | 2 |
| CLUEVO | 1 | 2 |
| CMONOS Co. Ltd. | 1 | 1 |
| CODECABIN | 1 | 1 |
| CODESYS | 77 | 797 |
| CODESYS V3 | 14 | 582 |
| COMMAX | 1 | 1 |
| CONTEC CO., LTD. | 1 | 13 |
| COREMOBILE Co. Ltd. | 1 | 1 |
| COWELL INFORMATION SYSTEM CO., LTD. | 1 | 1 |
| CP Plus | 1 | 1 |
| CREATE S.D CO., LTD. | 1 | 1 |
| CRIXP | 1 | 1 |
| CRM Perks | 9 | 11 |
| CROSSCERT | 1 | 1 |
| CRUDLab | 2 | 3 |
| CTF-hacker | 1 | 1 |
| CTHthemes | 1 | 1 |
| CURL | 1 | 31 |
| CVE-2019-6813 | 2 | 4 |
| CVE-2019-6837 | 1 | 3 |
| CVEProject | 1 | 2 |
| CZ.NIC | 1 | 4 |
| C\/c\+\+ Advanced Lint Project | 1 | 1 |
| Ca | 98 | 485 |
| Ca3de | 1 | 2 |
| Ca Lottery Results Project | 1 | 1 |
| Ca Technologies | 1 | 4 |
| Cab Booking Script Project | 1 | 2 |
| Cabextract | 1 | 17 |
| Cabextract Project | 1 | 9 |
| Cable-modems | 1 | 2 |
| Cabletron | 2 | 2 |
| Cabron Connector | 1 | 1 |
| Cabsoftware | 1 | 1 |
| Cacagoo | 1 | 2 |
| Cacert | 1 | 1 |
| Cache Project | 1 | 7 |
| Cached-path-relative Project | 1 | 1 |
| Cacheflow | 1 | 2 |
| Cacheguard | 1 | 1 |
| Cacti | 3 | 131 |
| Cactus Software | 1 | 2 |
| Cactushop | 1 | 5 |
| Cactusoft | 3 | 10 |
| Cactusthemes | 1 | 1 |
| Cactusvpn | 1 | 2 |
| Caddy Project | 1 | 7 |
| Caddyserver | 1 | 7 |
| Cadenix | 1 | 1 |
| Cadpage | 1 | 1 |
| Cadsoft | 1 | 3 |
| Caehealthcare | 1 | 1 |
| Cafe Billing System Project | 1 | 1 |
