What is the __cf_bm cookie?
Cloudflare's bot products identify and mitigate automated traffic to protect your site from bad bots. Cloudflare places the __cf_bm cookie on End User devices that access Customer sites that are protected by Bot Management or Bot Fight Mode. The __cf_bm cookie is necessary for the proper functioning of these bot solutions.
Our October 2026 scan found it on 719 sites (29% of the 2,450 we scanned), set before any consent.
- Purpose
- Functional
- Belongs to
- Cloudflare
- Set as
- First-party on 46% of sites, third-party on 54%
- Typical lifetime
- Under a day (vendor says: session)
Sites that set __cf_bm before consent
The highest-ranked 30 of 719 sites.
- cloudflare.com2 tracking companies
- linkedin.com0 tracking companies
- roblox.com0 tracking companies
- vimeo.com0 tracking companies
- openai.com1 tracking company
- yuga.com5 tracking companies
- samsung.com4 tracking companies
- epicgames.com1 tracking company
- webex.com4 tracking companies
- applovin.com8 tracking companies
Show 20 more sites
- base.org2 tracking companies
- w3.org0 tracking companies
- soundcloud.com7 tracking companies
- cnn.com5 tracking companies
- bbc.com4 tracking companies
- nist.gov3 tracking companies
- canva.com1 tracking company
- cpanel.net4 tracking companies
- hubspot.com1 tracking company
- pubmatic.com1 tracking company
- roku.com3 tracking companies
- hcaptcha.com0 tracking companies
- namecheap.com4 tracking companies
- forter.com3 tracking companies
- tinyurl.com2 tracking companies
- amplitude.com5 tracking companies
- inmobi.com12 tracking companies
- weather.com4 tracking companies
- name.com3 tracking companies
- weebly.com1 tracking company
Related cookies
Other cookies from Cloudflare.
- cf_clearance226 sites
- _cfuvid156 sites
- __cflb26 sites
How to stop it
Declining non-essential cookies in a site's consent banner should stop __cf_bm being set on later visits. Blocking third-party cookies in your browser settings stops the third-party kind everywhere, and clearing cookies for a site removes any it already set.
Description from the Open Cookie Database (Apache 2.0).
Understanding this page
- How cookie lifetimes work, and why a 13-month _ga matters
What a cookie's "expires" field actually controls, why Google Analytics ships a 2-year default that many sites cut down to 13 months, and how Safari's 7-day cap on script-set cookies changes the picture.
- First-party vs third-party cookies (and why "first-party" still tracks you)
What the distinction actually means technically, why browsers only block one of the two, and how CNAME cloaking, server-side tagging and cookies like _ga let sites keep tracking under their own domain.
- How to block or limit trackers
Browser privacy settings, content blockers, Global Privacy Control and clearing cookies compared honestly — what each one actually stops, what it doesn't, and what it costs you in return.