Theori
Category: AI in Cybersecurity
Offensive cybersecurity company building AI-powered security testing solutions, founded by world-class white-hat hackers with record DEF CON wins Theori was founded in 2016. The company is led by Brian (Se-jun) Pak. Based in Austin, Texas, United States (HQ); Seoul, South Korea (R&D). Team size: 51-200. Total funding raised: $17.3M. Latest round: Seed. Key investors include K2G Fund (Asia2G Capital), Dunamu (두나무), NAVER D2 Startup Factory, Hana Bank, ATON (아톤).
- Founded
- 2016
- Headquarters
- Austin, Texas, United States (HQ); Seoul, South Korea (R&D)
- Team size
- 51-200
- Total funding
- $17.3M
Value proposition
AI-powered offensive security that combines world-class hacker expertise with autonomous AI agents (Xint, Xint Code) to find vulnerabilities faster and more accurately than traditional pentesting or scanners
Products and solutions
Xint family: Xint Web (AI black-box / autonomous pentesting), Xint Code (LLM-native SAST), Xint Pulse (on-demand black-box pentesting, launched Jul 2026), αprism (LLM Guard & Monitoring), Dreamhack (cybersecurity education, 75K+ members), Dreamhack Enterprise, Offensive Security Consulting, AI Red Teaming, STaaS, ChainLight (blockchain security), Fermium-252 (threat intelligence)
Unique value
Only company combining 9x DEF CON winning hacker expertise with proprietary AI agents (Xint Web/Code/Pulse) that autonomously discover zero-days — proven by CVE-2026-31431 (Copy Fail) Linux kernel (~1 hour) and critical Apple OS findings credited to Xint Code; IDC Innovator for agentic autonomous pentesting (Aug 2026)
Target customer
Global enterprises, technology companies, financial institutions, blockchain/crypto firms, government agencies, and defense organizations needing advanced security testing and vulnerability discovery
Industries served
Cybersecurity, Technology, Finance/Fintech, Blockchain/Crypto, Telecommunications, Government/Defense, Cloud Infrastructure
Technology advantage
World's most decorated competitive hacking team (9x DEF CON wins incl. 4th straight at DEF CON 33, 70+ international CTF wins); AI models trained on elite hacker knowledge; Xint Code analyzes millions of LOC in <12 hours; DARPA AIxCC semifinal 1st ($2M) and finals 3rd ($1.5M); Apple OS and Linux kernel zero-days found by Xint Code; IDC Innovator for agentic autonomous pentesting
How they differentiate
Unlike traditional pentesting firms or bug bounty platforms, Theori combines elite hacker talent (9x DEF CON winners) with proprietary AI agents that autonomously discover vulnerabilities at scale. Xint Code is an LLM-native SAST that analyzes millions of lines of code in hours, not weeks, and finds business logic flaws that traditional scanners miss. The company has proven its AI can discover critical zero-days like CVE-2026-31431 (Copy Fail) in the Linux kernel.
Main competitors
HackerOne; Bugcrowd; Pentera; CrowdStrike; Synack
Key partnerships
Okta (strategic cybersecurity partnership), POSCO DX (AI-driven security framework), ATON (AI security MOU / strategic investor, Mar 2026), POSTECH (AI/IT security research & talent, 2026), Samsung Electronics (Xint customer), Microsoft (Windows OS security verification), Google (Chrome vulnerability discovery), NAVER, Dunamu (두나무), LucentBloc, LG Electronics
Notable customers
Samsung Electronics, Microsoft, Google, Okta, NAVER, Dunamu, Toss, LG Electronics, POSCO DX, Hyundai Mobis, Woori Financial Group (Xint Web, Aug 2026)
Major milestones
2016: Company founded in Austin, TX, 2017: Theori Korea established, 2018: NAVER D2 Startup Factory investment, 2020: Dreamhack launched, 2022: $15.5M seed led by K2G Fund, 2024: DARPA AIxCC semifinal 1st ($2M), Presidential Commendation, 2025: Xint launched, αprism beta, Okta partnership, DEF CON 33 9th win + AIxCC finals 3rd ($1.5M)
Growth metrics
87 employees (2026-03, Korea entity); 100+ total (2025); 60K+ Dreamhack members; 100+ enterprise clients globally; 150+ vulnerabilities found by Xint in beta
Market positioning
Premium offensive security provider bridging elite human hacking expertise with AI automation; positioned as a high-end alternative to both traditional pentesting consultancies and automated scanners; expanding from consulting to SaaS product model with Xint and Xint Code
Geographic focus
Global (HQ in Austin, TX; major R&D in Seoul, Korea); targeting North American and Asian enterprise markets; 2026 focus on North America expansion
Patents and IP
1 patent filed (2025-06-09, Korea); ISO/IEC 27001:2022 and ISO/IEC 27017 certified (dual, Jun 2026); SOC 2 Type II compliant (Aug 2026)
About Brian (Se-jun) Pak
Ex-Kaprica Security Co-founder; Ex-Lockheed Martin Intern; Carnegie Mellon University BS/MS Computer Science; DEF CON record 9x winner; Founded PPP (Plaid Parliament of Pwning) hacking team at CMU
Latest news about Theori
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Official website: https://theori.io