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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
24,296
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() function#1478633Injection and Smuggling2022-05-16$6,000116
Cloudflare CASB Confused Deputy Problem#1952124No weakness recorded2023-06-07$3,30097
Using special IPv4-mapped IPv6 addresses to bypass local IP ban#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 Forwarding#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 it#3211031Cross-site Scripting2025-09-30$55075
Yet Another CASB Integration Takeover of Active Integrations#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 AccessTempAuth#3423950Cross-site Scripting2026-04-14–63
AI Playground XSS to steal user-chat messages and access to connected MCP Server#3424998Cross-site Scripting2026-02-26–62
Bypass R2 payment screen#2170559Authentication2023-11-10$35057

Subdomains24,296

Root
Scope
Name suggests:Mail
First seen
Text fileClear filters25 names
Subdomains of Cloudflare Public Bug Bounty
NameScopeFirst seen
mail.cloudflare.commailIn scope2026-11-14
alm.alertmedia.mail.cloudflare.commailIn scope2026-11-14
email.px.mail.cloudflare.commailIn scope2026-11-14
staging.mail.cloudflare.commail, stagingIn scope2026-11-14
stg.mail.cloudflare.commail, stagingIn scope2026-11-14
mx.cloudflare.commailIn scope2026-11-14
autodiscover.dairystatecheese.com.kip.ns.cloudflare.commailIn scope2026-11-14
webmail.texsani.com.lloyd.ns.cloudflare.commailIn scope2026-11-14
mail.ns.cloudflare.commailIn scope2026-11-14
smtp.cloudflare.commailIn scope2026-11-14
autodiscover.staging.cloudflare.commail, stagingIn scope2026-11-14
mail.trustandsafety.cloudflare.commailIn scope2026-11-14
autodiscover.cloudflareaccess.commailNot in the scope2026-11-14
click2mail.cloudflareaccess.commailNot in the scope2026-11-14
exchange.cloudflareaccess.commailNot in the scope2026-11-14
free2mail.cloudflareaccess.commailNot in the scope2026-11-14
imap.cloudflareaccess.commailNot in the scope2026-11-14
mail.cloudflareaccess.commailNot in the scope2026-11-14
mail1.cloudflareaccess.commailNot in the scope2026-11-14
mail2.cloudflareaccess.commailNot in the scope2026-11-14
mx.cloudflareaccess.commailNot in the scope2026-11-14
owa.cloudflareaccess.commailNot in the scope2026-11-14
pop3.cloudflareaccess.commailNot in the scope2026-11-14
smtp.cloudflareaccess.commailNot in the scope2026-11-14
webmail.cloudflareaccess.commailNot in the scope2026-11-14

18,933 names are covered by the program's own scope; 0 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 2026-11-14.

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