CVE-2025-14022 is a vulnerability identified in the LINE client for iOS, specifically affecting versions prior to 15.4. The root cause lies in an integrated financial SDK within the application that improperly handles SSL/TLS certificate validation. This SDK interferes with the app's network processing, effectively disabling server certificate verification for a substantial portion of the app's network traffic. As a result, an attacker positioned on the same network or within network proximity (network-adjacent) can exploit this flaw to conduct man-in-the-middle (MitM) attacks. Such attacks allow interception, eavesdropping, or modification of encrypted communications that the app transmits, severely compromising the confidentiality and integrity of user data. The vulnerability is classified under CWE-295, which relates to improper certificate validation. The CVSS v3.1 base score is 7.7 (high severity), reflecting the network attack vector, no required privileges or user interaction, but high attack complexity due to the need for network adjacency. Although no known exploits have been reported in the wild, the potential impact on sensitive financial and personal data transmitted via LINE is significant. The vulnerability affects only the iOS client, specifically version 15.3 and earlier, and is expected to be resolved in version 15.4 or later. The lack of patch links suggests the fix may be pending or recently released. The technical details emphasize the importance of proper SSL/TLS validation in integrated SDKs, especially those handling financial data, to prevent undermining the security guarantees of encrypted communications.

For European organizations, this vulnerability poses a significant risk to the confidentiality and integrity of communications conducted over the LINE iOS client. Given LINE's integration of financial services, intercepted data could include sensitive financial transactions, personal information, and corporate communications. This could lead to data breaches, financial fraud, or espionage. The man-in-the-middle attack vector means that attackers on public or compromised networks (e.g., Wi-Fi hotspots, corporate networks with insider threats) could exploit this vulnerability without needing user interaction or elevated privileges. The disruption to trust in encrypted communications could also impact business operations and user confidence. While availability impact is low, the potential for data manipulation and interception is high. European organizations with employees or customers using LINE on iOS devices are at risk, particularly those in finance, legal, or sectors handling sensitive personal data. The vulnerability could also facilitate further attacks by exposing session tokens or credentials.

1. Immediate update: Organizations and users should upgrade the LINE client for iOS to version 15.4 or later as soon as the patch is available to restore proper SSL/TLS certificate validation. 2. Network monitoring: Deploy network intrusion detection systems (NIDS) capable of detecting anomalous SSL/TLS traffic patterns or MitM attempts, especially on corporate Wi-Fi and VPNs. 3. Enforce use of trusted networks: Encourage or enforce the use of trusted, encrypted networks and VPNs for accessing LINE, reducing exposure to network-adjacent attackers. 4. Application whitelisting and sandboxing: Limit the ability of unauthorized SDKs or apps to interfere with network traffic on iOS devices through mobile device management (MDM) policies. 5. User awareness: Educate users about the risks of using public or unsecured Wi-Fi networks and the importance of updating applications promptly. 6. Incident response readiness: Prepare to investigate potential data breaches or suspicious activity related to LINE communications, including logs and network captures. 7. Vendor engagement: Maintain communication with LINE Corporation for timely updates and security advisories related to this vulnerability.