About
About Stella.
Stella LLC (合同会社Stella) is an independent security research company based in Tokyo. Our research covers everything from low-level C/C++ infrastructure software to web applications.
What we doIndependent research on the software the internet runs on.
Stella conducts independent security research from low-level code to web applications. At the low level, we study C/C++ infrastructure software — cryptographic and network-protocol libraries, VPN daemons, DNS servers, routers, and database infrastructure — and firmware, looking at how they handle untrusted input and finding memory-corruption and protocol vulnerabilities. On the web side, we examine application and framework code for vulnerabilities. We report what we find to the vendors who maintain the code.
How we workCoordinated disclosure, done carefully.
Every finding is reported privately to the maintaining vendor first. We work with each vendor's security team through their coordinated-disclosure process — reproducing the issue, confirming the fix, and respecting embargo timelines — so that details become public only after a patch is available or the vendor's embargo ends.
STEP 01
Report
We first report the vulnerability to the vendor, privately.
STEP 02
Confirm the fix
We confirm the issue with the vendor and verify the fixed release.
STEP 03
Publish
We publish the details once the fix ships, or on the agreed disclosure date.
Founder
Haruto Kimura
Founder & CEO
Security researcher and engineer focused on memory-corruption vulnerabilities in C/C++ infrastructure software. Credited on findings across cryptographic libraries (wolfSSL, NSS), VPN implementations (strongSwan), and DNS infrastructure (PowerDNS).
LinkedIn ↗GitHub ↗X (Twitter) ↗
Background
2026 – PresentCEO
Stella LLC
Education
2023 – 2026M.Sc., Computer Science & Engineering
Waseda University
2024 – 2025Exchange Program, Computing & Information Systems
The University of Melbourne
2019 – 2023B.Sc., Applied Mathematics
Waseda University
Member
Haruki Oyama
Principal Security Researcher
Education
2026 – PresentMaster's in Computer Science and Communications Engineering
Waseda University
2022 – 2026Major in Computer Science and Communications Engineering
Waseda University
Early admission · School of Fundamental Science and Engineering Dean's Award for Academic Excellence
Timeline
From first research to 48 CVEs.
2025Research begins
Stella's founder begins focused research into memory-corruption vulnerabilities in C/C++ infrastructure software.
Q1 2026First CVEs assigned
wolfSSL and Mbed TLS vulnerabilities discovered and responsibly disclosed.
Q2 202632 CVEs assigned
Expanded to strongSwan, PowerDNS, GnuTLS, and PostgreSQL/PgBouncer.
October 2026Team total: 48 CVEs
Founder Kimura and member Oyama together: 48 CVEs and JPY 17 million in bug bounty rewards (as of October 2026).
OngoingContinued coordinated disclosure
Stella continues independent research and coordinated disclosure across C/C++ infrastructure software.
Company
Stella LLC
- Company
- Stella LLC (合同会社Stella)
- Founded
- March 2026
- Representative
- CEO Haruto KimuraGitHub ↗X ↗LinkedIn ↗
- Business
- Software vulnerability research and security research
- Address
- BIG Office Plaza Ikebukuro 1206, 2-62-8 Higashi-Ikebukuro, Toshima-ku, Tokyo 170-0013, Japan
- Contact
- contact@stellasec.ai