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Bug bounty program

CP

Cloudflare Public Bug Bounty

Open on HackerOneAtlas
Platform
HackerOne
Bounties
Pays
Assets in scope
51
Disclosed reports
44
Subdomains
24,298
Vendor on CyberSIXT
Cloudflare (70 CVEs, 0 exploited)

Most upvoted reports44

All reports
Most upvoted reports of Cloudflare Public Bug Bounty
ReportWeaknessDisclosedBountyVotes
HTTP Request Smuggling in Transform Rules using hexadecimal escape sequences in the concat() functionAnalysed#1478633Injection and Smuggling2022-05-16$6,000116
Cloudflare CASB Confused Deputy ProblemAnalysed#1952124No weakness recorded2023-06-07$3,30097
Using special IPv4-mapped IPv6 addresses to bypass local IP banAnalysed#1785260No weakness recorded2023-01-24$7,50078
Bypass of Cloudflare's Cache Keys and WAF via header overflow#3027461Access Control2025-11-18–77
Hijack all emails sent to any domain that uses Cloudflare Email ForwardingAnalysed#1419341Access Control2022-07-28$6,00076
`use-mcp`'s oauth2 process uses a window.open call with untrusted mcp server provided data allowing for code execution under the page using itAnalysed#3211031Cross-site Scripting2025-09-30$55075
Yet Another CASB Integration Takeover of Active IntegrationsAnalysed#2094346No weakness recorded2023-11-13–68
[Variation of #3321406] YetAnother 1-Click Chaining of Self-XSS, Cookie Tossing and AntiCSRF Token Prediction leads to auto approval in AccessTempAuthAnalysed#3423950Cross-site Scripting2026-04-14–63
AI Playground XSS to steal user-chat messages and access to connected MCP ServerAnalysed#3424998Cross-site Scripting2026-02-26–62
Bypass R2 payment screenAnalysed#2170559Authentication2023-11-10$35057

Subdomains24,298

Root
Scope
Name suggests
First seen
Text file24,298 names
Subdomains of Cloudflare Public Bug Bounty
NameScopeFirst seen
cf-199-27-128-195.cloudflare.comIn scope2026-11-14
cf-199-27-128-196.cloudflare.comIn scope2026-11-14
cf-199-27-128-197.cloudflare.comIn scope2026-11-14
cf-199-27-128-198.cloudflare.comIn scope2026-11-14
cf-199-27-128-199.cloudflare.comIn scope2026-11-14
cf-199-27-128-20.cloudflare.comIn scope2026-11-14
cf-199-27-128-200.cloudflare.comIn scope2026-11-14
cf-199-27-128-201.cloudflare.comIn scope2026-11-14
cf-199-27-128-202.cloudflare.comIn scope2026-11-14
cf-199-27-128-203.cloudflare.comIn scope2026-11-14
cf-199-27-128-204.cloudflare.comIn scope2026-11-14
cf-199-27-128-205.cloudflare.comIn scope2026-11-14
cf-199-27-128-206.cloudflare.comIn scope2026-11-14
cf-199-27-128-207.cloudflare.comIn scope2026-11-14
cf-199-27-128-208.cloudflare.comIn scope2026-11-14
cf-199-27-128-209.cloudflare.comIn scope2026-11-14
cf-199-27-128-21.cloudflare.comIn scope2026-11-14
cf-199-27-128-210.cloudflare.comIn scope2026-11-14
cf-199-27-128-211.cloudflare.comIn scope2026-11-14
cf-199-27-128-212.cloudflare.comIn scope2026-11-14
cf-199-27-128-213.cloudflare.comIn scope2026-11-14
cf-199-27-128-214.cloudflare.comIn scope2026-11-14
cf-199-27-128-215.cloudflare.comIn scope2026-11-14
cf-199-27-128-216.cloudflare.comIn scope2026-11-14
cf-199-27-128-217.cloudflare.comIn scope2026-11-14
cf-199-27-128-218.cloudflare.comIn scope2026-11-14
cf-199-27-128-219.cloudflare.comIn scope2026-11-14
cf-199-27-128-22.cloudflare.comIn scope2026-11-14
cf-199-27-128-220.cloudflare.comIn scope2026-11-14
cf-199-27-128-221.cloudflare.comIn scope2026-11-14
cf-199-27-128-222.cloudflare.comIn scope2026-11-14
cf-199-27-128-223.cloudflare.comIn scope2026-11-14
cf-199-27-128-224.cloudflare.comIn scope2026-11-14
cf-199-27-128-225.cloudflare.comIn scope2026-11-14
cf-199-27-128-226.cloudflare.comIn scope2026-11-14
cf-199-27-128-227.cloudflare.comIn scope2026-11-14
cf-199-27-128-228.cloudflare.comIn scope2026-11-14
cf-199-27-128-229.cloudflare.comIn scope2026-11-14
cf-199-27-128-23.cloudflare.comIn scope2026-11-14
cf-199-27-128-230.cloudflare.comIn scope2026-11-14
cf-199-27-128-231.cloudflare.comIn scope2026-11-14
cf-199-27-128-232.cloudflare.comIn scope2026-11-14
cf-199-27-128-233.cloudflare.comIn scope2026-11-14
cf-199-27-128-234.cloudflare.comIn scope2026-11-14
cf-199-27-128-235.cloudflare.comIn scope2026-11-14
cf-199-27-128-236.cloudflare.comIn scope2026-11-14
cf-199-27-128-237.cloudflare.comIn scope2026-11-14
cf-199-27-128-238.cloudflare.comIn scope2026-11-14
cf-199-27-128-239.cloudflare.comIn scope2026-11-14
cf-199-27-128-24.cloudflare.comIn scope2026-11-14
cf-199-27-128-240.cloudflare.comIn scope2026-11-14
cf-199-27-128-241.cloudflare.comIn scope2026-11-14
cf-199-27-128-242.cloudflare.comIn scope2026-11-14
cf-199-27-128-243.cloudflare.comIn scope2026-11-14
cf-199-27-128-244.cloudflare.comIn scope2026-11-14
cf-199-27-128-245.cloudflare.comIn scope2026-11-14
cf-199-27-128-246.cloudflare.comIn scope2026-11-14
cf-199-27-128-247.cloudflare.comIn scope2026-11-14
cf-199-27-128-248.cloudflare.comIn scope2026-11-14
cf-199-27-128-249.cloudflare.comIn scope2026-11-14
cf-199-27-128-25.cloudflare.comIn scope2026-11-14
cf-199-27-128-250.cloudflare.comIn scope2026-11-14
cf-199-27-128-26.cloudflare.comIn scope2026-11-14
cf-199-27-128-27.cloudflare.comIn scope2026-11-14
cf-199-27-128-28.cloudflare.comIn scope2026-11-14
cf-199-27-128-29.cloudflare.comIn scope2026-11-14
cf-199-27-128-60.cloudflare.comIn scope2026-11-14
cf-199-27-128-61.cloudflare.comIn scope2026-11-14
cf-199-27-128-62.cloudflare.comIn scope2026-11-14
cf-199-27-128-63.cloudflare.comIn scope2026-11-14
cf-199-27-128-64.cloudflare.comIn scope2026-11-14
cf-199-27-128-65.cloudflare.comIn scope2026-11-14
cf-199-27-128-66.cloudflare.comIn scope2026-11-14
cf-199-27-128-67.cloudflare.comIn scope2026-11-14
cf-199-27-128-68.cloudflare.comIn scope2026-11-14
cf-199-27-128-69.cloudflare.comIn scope2026-11-14
cf-199-27-128-70.cloudflare.comIn scope2026-11-14
cf-199-27-128-71.cloudflare.comIn scope2026-11-14
cf-199-27-128-72.cloudflare.comIn scope2026-11-14
cf-199-27-128-73.cloudflare.comIn scope2026-11-14
cf-199-27-128-74.cloudflare.comIn scope2026-11-14
cf-199-27-128-75.cloudflare.comIn scope2026-11-14
cf-199-27-128-76.cloudflare.comIn scope2026-11-14
cf-199-27-128-77.cloudflare.comIn scope2026-11-14
cf-199-27-128-78.cloudflare.comIn scope2026-11-14
cf-199-27-128-79.cloudflare.comIn scope2026-11-14
cf-199-27-128-80.cloudflare.comIn scope2026-11-14
cf-199-27-128-81.cloudflare.comIn scope2026-11-14
cf-199-27-128-82.cloudflare.comIn scope2026-11-14
cf-199-27-128-83.cloudflare.comIn scope2026-11-14
cf-199-27-128-84.cloudflare.comIn scope2026-11-14
cf-199-27-128-85.cloudflare.comIn scope2026-11-14
cf-199-27-128-86.cloudflare.comIn scope2026-11-14
cf-199-27-128-87.cloudflare.comIn scope2026-11-14
cf-199-27-128-88.cloudflare.comIn scope2026-11-14
cf-199-27-128-89.cloudflare.comIn scope2026-11-14
cf-199-27-128-90.cloudflare.comIn scope2026-11-14
cf-199-27-128-91.cloudflare.comIn scope2026-11-14
cf-199-27-128-92.cloudflare.comIn scope2026-11-14
cf-199-27-128-93.cloudflare.comIn scope2026-11-14

18,935 names are covered by the program's own scope; 2 were first seen this week. Names come from ProjectDiscovery's public Chaos dataset (passive sources: certificate logs, DNS and other public data), matched to the program by its listing and its own domain scope. A name being in a dataset is not permission to test it: only what the program's own scope says is in scope, and its policy decides. CyberSIXT does not resolve, probe or scan these names. Tags come from the name alone. Source: ProjectDiscovery Chaos. Subdomains on the Atlas, or search the subdomains of every program.

A name in a dataset is not permission to test it: the program's own scope and rules decide. Data as of 2026-11-15.

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