LINE Yahoo Says 7.1 Million Internal IDs Sent to Ad Tool Over 4 Years
A four-year leak of internal identifiers from LINE GAME titles reveals the risk of data oversharing in ad tech integrations, even when no personal information is exposed.
Reporting from 1 source: ASCII.jp.
LINE Yahoo disclosed on July 13 that internal identifiers from three LINE GAME titles were sent to an external advertising tool from May 2022 to April 2026. The company stated that approximately 7.1 million login-state identifiers were involved, but no personal information was included. The cause was insufficient configuration checks when the tool's settings were changed. Transmission has been stopped.
LINE Yahoo's data disclosure on July 13 covers three mobile game titles: LINE Poko Poko, LINE Pokopan Town, and LINE Pokopan. The company said internal identifiers for logged-in users of these games were sent to an external advertising tool from May 2022 to April 2026 - a period of roughly four years. The identifiers were random strings used internally to recognize users, not the LINE ID used for adding friends. The total count of exposed identifiers reached about 7.1 million. LINE Yahoo attributed the leak to insufficient configuration checks by both itself and the partner company when the tool's settings were changed. The company confirmed that transmission has been stopped and that no personal information was included.
Synthesized by Yomimono from the 1 cited source below, including Japanese-language reporting where cited, then editorially reviewed before publishing.