Cloudflare cf_clearance: why it expires and how to stop the re-challenge loop

Short summary

Cloudflare cf_clearance cookies expire and bind strictly to the IP, User-Agent, and TLS fingerprint that obtained them—rotating proxies or changing UA mid-session triggers an infinite re-challenge loop. The fix: pin one IP, UA, and fingerprint per session, detect re-challenges via response headers, and evict-then-remint the cookie instead of replaying an invalid one. Includes code examples and debugging checklist.

• •cf_clearance is bound to IP, User-Agent, and TLS fingerprint; changing any triggers re-challenges
• •Rotating proxies or changing User-Agent mid-session causes infinite re-challenge loops
• •Solution: maintain consistent context, detect challenges via cf-mitigated header, evict and remint instead of retrying

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