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Open Bug Bounty named among the
Top 5 Bug Bounty programs of 2021
by The Hacker News

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1,647,945 coordinated disclosures
1,296,475 fixed vulnerabilities
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42,009 researchers, 1,626 honor badges

reinforchu | Security Researcher Profile

Security researcher reinforchu has already helped fix 12 vulnerabilities.

Researcher reputation:  30

Real name:
Tsubasa FUJII

About me:
Web security researcher(Japanese)
Home server rack user


Contact email:[PGP] F755 EA05 F5E4 1F65 BA48 7CE0 3AFD C323 1532 9299

Alternative Contacts:
[email protected]

Certifications & Diplomas:
Diploma in Information Technology:
IPA, Japan: IP, SG, FE
Microsoft: AZ-900

Experience in Application Security
over 5 years

Award / Bug Bounty I prefer:
A small amount is fine, so please donate.
You may include my name in the acknowledgments.

Halls of Fame:
CVE-2019-8670, CVE-2021-36215
Bug bounty of Microsoft Azure (March 2020) - App Service important vulnerability
APPLE-SA-2020-11-13(WebKit Security-bug fix)
Bug bounty of Google Chrome VRP

Follow me on:

Ethics and Rules:
Tsubasa FUJII is required to abide by the ethics and rules of the Open Bug Bounty project. If you reasonably believe that rules are not respected, please report this to us.

Recommendations and Acknowledgements

@MitsuhashiN     5 January, 2021
    Twitter MitsuhashiN Takeo Arai from JST:
Thank you for reporting our website vulnerability.
For your useful informations, we could fix them.
@kushidat     18 January, 2021
    Twitter kushidat Tatsuya Kushida from RIKEN BRC:
Thank you so much for suggesting the vulnerability. The prompt and detailed response helped solve the issues.

Please login via Twitter to add a recommendation

Honor Badges

Number of Secured Websites

10+ Secured Websites Badge
50+ Secured Websites Badge
500+ Secured Websites Badge
Web Security Veteran Badge
10+ Websites
50+ Websites
500+ Websites
1000+ Websites

Advanced Security Research

WAF Bypasser Badge
CSRF Master Badge
AppSec Logic Master Badge
Fastest Fix Badge
WAF Bypasser
CSRF Master
30+ Reports
AppSec Logic Master
30+ Reports
Fastest Fix
Fix in 24 hours

Outstanding Achievements

Secured OBB Badge
OBB Advocate Badge
Improved OBB Badge
Secured OBB
OBB Advocate
Improved OBB

Commitment to Remediate and Patch

Patch Master Badge
Patch Guru Badge
Patch Lord Badge
Patch Master
55% Patched
Patch Guru
65% Patched
Patch Lord
75% Patched

Recommendations and Recognition

10+ Recommends
25+ Recommends
50+ Recommends

Distinguished Blog Author

Distinguished Blog Author Badge
Distinguished Blog Author Badge
Distinguished Blog Author Badge
1 Post
3 Posts
5+ Posts

Research Statistics

Total reports:24
Total patched vulnerabilities:12
Recommendations received:2
Active since:25.12.2020

Reported Vulnerabilities

All Submissions

No posts in blog yet

  Latest Patched


  Latest Blog Posts

04.12.2023 by BAx99x
Unmasking the Power of Cross-Site Scripting (XSS): Types, Exploitation, Detection, and Tools
04.12.2023 by a13h1_
$1120: ATO Bug in Twitter’s
04.12.2023 by ClumsyLulz
How I found a Zero Day in W3 Schools
04.12.2023 by 24bkdoor
Hack the Web like a Pirate: Identifying Vulnerabilities with Style
04.12.2023 by 24bkdoor
Navigating the Bounty Seas with Open Bug Bounty

  Recent Recommendations

    23 November, 2023
Grace à Hatim_cf on a pu corrigé une faille mineure de sécurité.
    22 November, 2023
On behalf of our users on one of the pages hosted at, I'd like to thank Niko for his effort in finding and responsibly reporting an XSS vuln in one of our user's sites. The XSS was quickly patched after Niko's detailed report making the web a safer place again. Thanks!
    22 November, 2023
Ronald identified an XSS vulnerability on our site which could be fixed fast. Thanks for the provided information!
    4 November, 2023
Thank you for fixing the XSS vulnerability
    13 October, 2023
I am highly recommending Sajid for web assessments and penetrating testing. Sajid was highly professional and detailed in t heir approach towards finding vulnerabilities.