`__cf_bm`

Used by Cloudflare to tell automated traffic from human traffic. It is not used for advertising.

Owner: Cloudflare, Inc.
Matches: The exact name __cf_bm
Needed to Work: Yes. Removing it can sign you out or break the site.
Confidence: Verified
Source: https://developers.cloudflare.com/fundamentals/reference/policies-compliances/cloudflare-cookies/
Last Reviewed: 2026-09-13

Which Sites

Any site. The name is specific enough to identify this cookie wherever it appears.