Description
O2 UK before 2025-05-19 allows subscribers to determine the Cell ID of other subscribers by initiating an IMS (IP Multimedia Subsystem) call and then reading the utran-cell-id-3gpp field of a Cellular-Network-Info SIP header, aka an ECI (E-UTRAN Cell Identity) leak. The Cell ID might be usable to identify a cell location via crowdsourced data, and might correspond to a small physical area (e.g., if the called party is in a city centre). Removal of the Cellular-Network-Info header is mentioned in section 4.4.19 of ETSI TS 124 229.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| O2 UK | O2 | ≤ 2025-05-17 | — |
References
- https://mastdatabase.co.uk/blog/2025/05/o2-expose-customer-location-call-4g/
- https://news.ycombinator.com/item?id=44014046
- https://www.etsi.org/deliver/etsi_ts/124200_124299/124229/15.10.00_60/ts_124229v151000p.pdf
- https://www.ispreview.co.uk/index.php/2025/05/o2-uk-fixes-volte-flaw-that-exposed-user-mobile-location-data.html