| C0d3r | C0D3R-Dz | C0d3R'Z |
| C0dy | C0ncept | C0nd0r |
| C0ntex | C0ntexb | C0otlass |
| C0rrupt | C0wboy | C1c4Tr1Z |
| C3rb3r | C4SS!0 & H1ch4m | C4SS!0 G0M3S |
| C4uR | Cabezon Aurélien | Cabezon Aurelien |
| Caddis | Caddy Dz | Cade Cairns |
| Cagri Tepebasili | Cahya Wirawan | Cairnsc |
| Caleb James DeLisle | Calil Khalil | CallAX |
| Cal Leeming | Callum Murphy | Calum Hutton |
| Calvin Phang | CaMaLeoN | Cameron Childress |
| Cameron Hotchkies | Camille Myers | Camino |
| Camisade | Canberk BOLAT | Canberx |
| Can Bölük | Cano2 | Captain Hook |
| Carl Benedict | Carl Byington | Carl Hardwick |
| Carl Livitt | Carlo Di Dato | Carlo Pelliccioni |
| Carlos Barros | Carlos E. Vieira | Carlos Mario Penagos Hollmann |
| Carlos Ramirez L. | Carlos Ulver | Carnal0wnage |
| Carsten Book | Carsten Eiram | Cartel |
| Carter Yagemann | Cary Hooper | César Fernández |
| Casper41 | Cassius | Castillo |
| Catatonicprime | Cbayet | C.B.B.L |
| CCNA | Cd1zz & Iglesiasgg | Cdg393 |
| CDI | Ced.clerget@free.fr | Cedric Cochin |
| Cees-bart | Celil Ünüver | Cem Onat Karagun |
| CeNGiZ-HaN | Cenjan | Cenobyte |
| CENSORED Search Vulnerabilities | Central Infosec | Cerberus Security Team |
| Certaindeath | Cesar Cerrudo | Cesar Neira |
| Cesaro | Cesar Tascon Alvarez | Ceylan Bozogullarindan |
| Cfreal | Cfreer | Cgisecurity |
| Ch0wn | CHackA0101 | Chad Kalmes |
| Chako | ChaMd5 | Chanam Park |
| Chance Proctor | ChaoticEvil | Chap0 |
| Chapman Schleiss | Chapp | Charalambous Glafkos |
| Charles Chear | Charles Dardaman | Charles Fol |
| Charles FOL | Charles Hooper | Charles M. Hannum |
| Charles Morris | Charles Reinold | Charles Stevenson |
| Charles Truscott | Charles Vaughn | Charlie Briggs |
| Charlie Miller | Chase Hatch | Chase Higgins |
| Chebuya | Che-Chun Kuo | CheebaHawk215 |
| Cheez Whiz | Cheffner | Cheki |
| Cheng Peng Su | ChernobiLe | Cheshireca7 |
| Chetanya Sharma | Cheverok | Chia Junyuan |
| Chicken Man | Chiekh Bouchenafa | China Nsl |
| CHINANSL Security Team | Chinchilla | Chintan Gurjar |
| Chip D3 Bi0s | Chiragh Arora | Chironex Fleckeri |
| Chi Tran | Chizuru Toyama | Chloe Chamberland |
| ChoiX | Chokri B.A | Chris |
| Chris Anastasio | Chris Anders | Chris Anley |
| Chris Barretto | Chris Benedict | Chris Boulton |
| Chris Castaldo | Chris Cooper | Chris Evans |
| Chris Gabriel | Chris Graham | Chris Hebert |
| Chris Hein | Chris Howie | Chris Inzinga |
| Chris John Riley | Chris Kellum | Chris Lyne |
| Chris McCurley | Chris Moberly | Chris Murtagh |
| Chris Porter | Chris Radigan | Chris Rock |
| Chris Russell | Chris Salls | Chris Sharp |
| Chris Thomas | Christian | Christian Borntraeger |
| Christian Bortone | Christian Catalano | Christian Galeone |
| Christian Haider | Christian Hammers | Christian Hoffmann |
| Christian Holler | Christian J. Eibl | Christian Lerrahn |
| Christian Mehlmauer | Christian Pappas | Christian Schneider |
| Christian Weiske | Christofer Dutz | Christophe Bailleux |
| Christophe Charron | Christophe De La Fuente | Christophe Devine |
| Christophe GRENIER | Christopher | Christopher Campbell |
| Christopher Kunz | Christopher Schwardt | Christopher Sogge Røtnes |
| Christophe VG | Christoph Mahrl | Christoph Schwarz |
| Chris Travers | Christy Philip Mathew | Chris Wedgwood |
| Chris Wood | CHT Security Research | Chuck Athey & Jim Garlick |
| Chujwamwdupe | Chunibalon | Chuzz |
| CIAC | Ciaran McNally | Cibbao |
| Cicklow | Cijfer | CiNU5 |
| Ciph3r | CipherTechs | CipherTechs Red Team |
| Ciri | Cisco Security | Cisco Talos |
| Citadelo | Citec Network Securities | Citril |
| Citynova | Civi | Cize0f |
| Ck@caroli.info | Cl24zy | Claepo Wang |
| Clément Lecigne | Clarity | Class101 |
| Claudio Andre | Claudio J. Lacayo | Claudio Viviani |
| Claudiu Calomfirescu | Claus R. F. Overbeck | Clemens Kurtenbach |
| Clement Billac | Clement Cruchet | Clement LECIGNE |
| Clément Lecigne | Clint Torrez | Cliph |
| Clorox | Cloud | Cmart |
| Cmaster4 | CMN | Cnaph |
| CO2 | CoBRa 21 | Cocoruder |
| Cod3in | Cod3rZ | Code Audit Labs |
| Codebreak | Codedreamer | CodeV |
| Code White | CodeXpLoder'tq | Cody Brocious |
| Cody Martin | Cody Pierce | Cody Sixteen |
| Cody T. - Hhp | Cody Tubbs | Cody Winkler |
| Cody Zacharias | Coeus Group | CoffeeBreakers |
| CoKi | Coksnuss | Cold Zero |
| Colette Chamberland | Colin Wong | Collin Mulliner |
| Collin R. Mulliner | Coloss | Colt7r |
| Compass Security | Computest | Computest.nl |
| ComSec | ConcorDHacK | COndemned |
| Condis | Connor McGarr | CoNqUeRoR |
| Cons0ul | Consultant.securite | Conviso |
| Coolest | CoolICE | Coolio |
| Coolkaveh | CoreLabs | Corelanc0d3r |
| CORE-SDI | Core Security | Core Security Technologies |
| Corey Lebleu | Corey Robinson | Corrado Liotta |
| CorryL | Corsaire Limited | CoRSaNTuRK |
| Corwin | Cory Eubanks | Cory Marsh |
| Co-Sarper-Der | COSIG | Cosmin Craciun |
| Courtesy Sentry Research Labs | CowPower | Cp77fk4r |
| CR45H3R | Cr4sh | Cr4wl3r |
| CraCkEr | Crackers Child | Crack MaN |
| Craig | Craig Arendt | Craig Davison |
| Craig Freyman | Craig Heffner | Craig Lambert |
| Craig Young | Crash | Crashbrz |
| Crashfr | Crash Over | CrAsh OVeR RIdE |
| Craw | CrAzY CrAcKeR | CrAzY.CrAcKeR |
| Crazy Hacker | Crc | Creamy Chicken Soup |
| Creatigon | Creosote | CrimsoN Loyd9 |
| Criolabs | Cristian Giustini | Cristiano Lincoln Mattos |
| Cristiano Maruti | Cristian Schipor | Crit3rion |
| Critical Security | Crlf | Croconile |
| Cronos | CrossWire | CRouland |
| Cru3l.b0y | Crux | CrYpTiC MauleR |
| CrZ | Cr@zy King | Csaba Barta |
| Csaba Fitzl | C.Schmitz | CSDT |
| CSW Research Lab | Ctacok | Ctacok & .:[melkiy]: |
| Cthulhu | CTurt | Cuctema |
| Cucura | Cult | Cupidon-3005 |
| CurcolHekerLink | Curesec Research Team | CvIr.System |
| CWD@rBe | CWH & Nafsh | CWH Underground |
| CXIb8O3 | Cxosmo | Cy83rl0gger |
| Cyanid-E | Cyb0r9 | Cyb3rt & 020 |
| Cyber-Crime | Cyber-Crystal | Cyber Flash |
| CyberGhost | CyberGrup Lojistik | Cyberlog |
| Cybermedia Software Private Limited | Cybermind | Cyber Security |
| Cyber Security Research Group | Cybertronic | Cyber.Zer0 |
| Cyber-Zone | Cyku Hong | CypherXero |
| CyRaX | Cyrill Bannwart | Cyrill Brunschwiler |
| Cyrillium Security | Cyrus The Gerat | Cyrus The Great |
| CyruxNET | | |
Vulmon