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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:API
First seen
Text fileClear filters107 names
Subdomains of Cloudflare Public Bug Bounty
NameScopeFirst seen
api.cloudflare.comapiIn scope2026-11-14
api-origin.cloudflare.comapiIn scope2026-11-14
au.api.cloudflare.comapiIn scope2026-11-14
docs.api.cloudflare.comapiIn scope2026-11-14
entrypoint-worker.api.cloudflare.comapiIn scope2026-11-14
gateway-entrypoint.api.cloudflare.comapiIn scope2026-11-14
canary.gateway.api.cloudflare.comapi, stagingIn scope2026-11-14
edge-production.gateway.api.cloudflare.comapiIn scope2026-11-14
production.gateway.api.cloudflare.comapiIn scope2026-11-14
api.blog.cloudflare.comapiIn scope2026-11-14
api-documentation-site.developers.cloudflare.comapiIn scope2026-11-14
api-documentation-site-v2.developers.cloudflare.comapiIn scope2026-11-14
bot-api.developers.cloudflare.comapiIn scope2026-11-14
edge-api.dex.cloudflare.comapiIn scope2026-11-14
edge-api.staging.dex.cloudflare.comapi, stagingIn scope2026-11-14
mainnet1-api.drand.cloudflare.comapiIn scope2026-11-14
mainnet2-api.drand.cloudflare.comapiIn scope2026-11-14
testnet-api.drand.cloudflare.comapiIn scope2026-11-14
api.fed.cloudflare.comapiIn scope2026-11-14
edge-iapi-certs-prod.api.fed.cloudflare.comapiIn scope2026-11-14
api.notifications.fed.cloudflare.comapiIn scope2026-11-14
api-staging.notifications.fed.cloudflare.comapi, stagingIn scope2026-11-14
api.staging.fed.cloudflare.comapi, stagingIn scope2026-11-14
edge-iapi-certs-staging.api.staging.fed.cloudflare.comapi, stagingIn scope2026-11-14
api.workers.fed.cloudflare.comapiIn scope2026-11-14
graphql.cloudflare.comapiIn scope2026-11-14
api.integrations.cloudflare.comapiIn scope2026-11-14
api.staging.integrations.cloudflare.comapi, stagingIn scope2026-11-14
api.labs-staging.cloudflare.comapi, stagingIn scope2026-11-14
cms-api.labs-staging.cloudflare.comadmin, api, stagingIn scope2026-11-14
demo-api.labs-staging.cloudflare.comapi, staging, testIn scope2026-11-14
api.labs.cloudflare.comapiIn scope2026-11-14
cms-api.labs.cloudflare.comadmin, apiIn scope2026-11-14
demo-api.labs.cloudflare.comapi, testIn scope2026-11-14
vcr-api.live.cloudflare.comapiIn scope2026-11-14
graphql.mcp.cloudflare.comapiIn scope2026-11-14
graphql-staging.mcp.cloudflare.comapi, stagingIn scope2026-11-14
api-proxy.notebooks.cloudflare.comapiIn scope2026-11-14
examples-api-proxy.notebooks.cloudflare.comapiIn scope2026-11-14
api.notifications.cloudflare.comapiIn scope2026-11-14
api-staging.notifications.cloudflare.comapi, stagingIn scope2026-11-14
api.privacy-auditability.cloudflare.comapiIn scope2026-11-14
staging-api.privacy-auditability.cloudflare.comapi, stagingIn scope2026-11-14
api.radar.cloudflare.comapiIn scope2026-11-14
worker-openapi-example.radar.cloudflare.comapiIn scope2026-11-14
api.realtime.cloudflare.comapiIn scope2026-11-14
api-devel.realtime.cloudflare.comapi, devIn scope2026-11-14
api-devel-2.realtime.cloudflare.comapi, devIn scope2026-11-14
api-gw-devel.realtime.cloudflare.comapi, devIn scope2026-11-14
api-silos.realtime.cloudflare.comapiIn scope2026-11-14
api-silos-devel.realtime.cloudflare.comapi, devIn scope2026-11-14
api0.realtime.cloudflare.comapiIn scope2026-11-14
api0.devel.realtime.cloudflare.comapi, devIn scope2026-11-14
api.staging.realtime.cloudflare.comapi, stagingListed out of scope2026-11-14
api-silos.staging.realtime.cloudflare.comapi, stagingIn scope2026-11-14
api0.staging.realtime.cloudflare.comapi, stagingIn scope2026-11-14
api.region.cloudflare.comNewapiIn scope2026-11-15
api.staging.region.cloudflare.comapi, stagingIn scope2026-11-14
05e2f63bd7f2ed7db1a88bbd0f8577a8.api.staging.region.cloudflare.comapi, stagingIn scope2026-11-14
6034e8d8d7d54d53a5e8fb5d93f21285.api.staging.region.cloudflare.comapi, stagingIn scope2026-11-14
6b1dcfa6e46b2a440f2a0660ae1a7b76.api.staging.region.cloudflare.comapi, stagingIn scope2026-11-14
8826eeeb4843efca82a4b4cb08a5d263.api.staging.region.cloudflare.comapi, stagingIn scope2026-11-14
9bff19a6e828d2a2ef5a8c94b3b12fc6.api.staging.region.cloudflare.comapi, stagingIn scope2026-11-14
cp-probe-fb1.api.staging.region.cloudflare.comapi, stagingIn scope2026-11-14
cp-probe-http.api.staging.region.cloudflare.comapi, stagingIn scope2026-11-14
cp-probe-nudge.api.staging.region.cloudflare.comapi, stagingIn scope2026-11-14
cp-probe-txt.api.staging.region.cloudflare.comapi, stagingIn scope2026-11-14
cp-probe-txt-le.api.staging.region.cloudflare.comapi, stagingIn scope2026-11-14
cp-probe-wc2.api.staging.region.cloudflare.comapi, stagingIn scope2026-11-14
cp-probe-wc3.api.staging.region.cloudflare.comapi, stagingIn scope2026-11-14
api.pricing.registrar.cloudflare.comapiIn scope2026-11-14
api-staging.pricing.registrar.cloudflare.comapi, stagingIn scope2026-11-14
api.production.speed.cloudflare.comapiIn scope2026-11-14
api.staging.speed.cloudflare.comapi, stagingIn scope2026-11-14
api.sqlite.cloudflare.comapiIn scope2026-11-14
staging.api.sqlite.cloudflare.comapi, stagingIn scope2026-11-14
api.staging.cloudflare.comapi, stagingIn scope2026-11-14
au.api.staging.cloudflare.comapi, stagingIn scope2026-11-14
edge-gateway.api.staging.cloudflare.comapi, stagingIn scope2026-11-14
edge-iapi-certs-staging.api.staging.cloudflare.comapi, stagingIn scope2026-11-14
entrypoint-worker.api.staging.cloudflare.comapi, stagingIn scope2026-11-14
eu.api.staging.cloudflare.comapi, stagingIn scope2026-11-14
gateway.api.staging.cloudflare.comapi, stagingIn scope2026-11-14
gateway-entrypoint.api.staging.cloudflare.comapi, stagingIn scope2026-11-14
temp-gateway.api.staging.cloudflare.comapi, stagingIn scope2026-11-14
api.one.dash.staging.cloudflare.comapi, stagingIn scope2026-11-14
vcr-api.live.staging.cloudflare.comapi, stagingIn scope2026-11-14
api.radar.staging.cloudflare.comapi, stagingIn scope2026-11-14
dash-api.verify.staging.cloudflare.comapi, stagingIn scope2026-11-14
api.teams.cloudflare.comapiIn scope2026-11-14
challenge-api.teams.cloudflare.comapiIn scope2026-11-14
api.workers.cloudflare.comapiIn scope2026-11-14
blog.api.www.cloudflare.comapiIn scope2026-11-14
api.cloudflareaccess.comapiNot in the scope2026-11-14
cdq-api.cloudflareaccess.comapiNot in the scope2026-11-14
cim-api.cloudflareaccess.comapiNot in the scope2026-11-14
cim-api-dev.cloudflareaccess.comapi, devNot in the scope2026-11-14
cim-api-qa.cloudflareaccess.comapi, testNot in the scope2026-11-14
cim-api-uat.cloudflareaccess.comapi, testNot in the scope2026-11-14
gws-api-sandbox.cloudflareaccess.comapi, testNot in the 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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