CVE-2025-48219

O2 UK through 2025-05-17 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.

Weakness

The code transmits data to another actor, but a portion of the data includes sensitive information that should not be accessible to that actor.

Potential Mitigations

• Compartmentalize the system to have “safe” areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
• Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/12.html
• https://cwe.mitre.org/data/definitions/217.html
• https://cwe.mitre.org/data/definitions/612.html
• https://cwe.mitre.org/data/definitions/613.html
• https://cwe.mitre.org/data/definitions/618.html
• https://cwe.mitre.org/data/definitions/619.html
• https://cwe.mitre.org/data/definitions/621.html
• https://cwe.mitre.org/data/definitions/622.html
• https://cwe.mitre.org/data/definitions/623.html

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