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CookieTosser

What is the st_uid cookie?

This cookie is used to store randomly generated unique browser identifier.

Our October 2026 scan found it on 5 sites (0% of the 2,450 we scanned), set before any consent.

Purpose
Advertising
Belongs to
Seedtag
Set as
First-party on 80% of sites, third-party on 20%
Typical lifetime
3 days (vendor says: 1 year) — shorter than the vendor documents

Sites that set st_uid before consent

The highest-ranked 5 of 5 sites.

How to stop it

Declining non-essential cookies in a site's consent banner should stop st_uid 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