Release notes for v96.0.3 are available at https://www.mozilla.org/en-US/firefox/96.0.3/releasenotes/ and state:
- Fixed an issue that allowed unexpected data to be submitted in some of our search telemetry (bug 1752317)
The Bugzilla bug report at https://bugzilla.mozilla.org/show_bug.cgi?id=1752317 has further details and notes that:
"In order to allow attribution of search by our partners, each partner assigns Firefox one or more “search codes”. This search code appears in the URL as an HTTP query parameter. Firefox Telemetry reports “search code” counts in order to help us ensure that the correct codes are being sent. This helps us detect defects as well as search engine “hijacking” by malware. We discovered some instances in which we believe, if a user (typically accidentally) edited that part of the URL, then the contents of that field were sent back in Telemetry....Note that search codes are not search queries (i.e. what you searched for). Unless edited as above, they do not include any unique or identifying information...
...Our investigation found that the unwanted data was rare – a maximum of 0.0013% of recorded events on Firefox Desktop ...
... In Firefox 96.0.3 we will be pushing a fix that limits collecting codes to a known list. This will still allow us to investigate potential search hijacking by malware by targeting specific values but will stop the unwanted collection of data. We have also started removing all submitted values not on the known list when the data is received by our telemetry servers. We will additionally remove all unknown values from existing data, which we expect to be completed by the end of February...."
Firefox users should review their data collection settings at Settings | Privacy & Security | Firefox Data Collection and Use (or enter about:preferences#privacy in the address bar). I always allow Firefox to send backlogged crash reports but I normally disable all other data collection.
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Dell Inspiron 5584 * 64-bit Win 10 Pro v21H2 build 19044.1466 * Firefox v96.0.3 * Microsoft Defender v.4.18.2111.5-1.1.18800.4 * Malwarebytes Premium v4.5.2.157-1.0.1562