Safari 26 blocks long-lived storage written by fingerprinting scripts

9 June 2025In force

Who is affected

All stores whose measurement relies on JavaScript-set cookies read in Safari

What it changes

Scripts identified as trackers can no longer write durable cookies or local storage, so Safari visitors are recounted as new on every visit.

What to do

Nothing to fix in your theme: this change comes from the browser, not from your store. It makes server-side measurement more reliable than anything depending on your visitor's browser.

Official source

webkit.orghttps://webkit.org/blog/16993/news-from-wwdc25-web-technology-coming-this-fall-in-safari-26-beta/

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All twenty-six changes