CVE-2025-5715 is a vulnerability identified in the Signal App version 7.41.4 on Android devices, specifically within the Biometric Authentication Handler component. The flaw results from a missing critical step in the authentication process, which could potentially allow an attacker with physical access to the device to bypass biometric authentication mechanisms. The vulnerability is characterized by a high attack complexity and difficult exploitation conditions, meaning that an attacker would require significant skill and access to the physical device to successfully exploit the flaw. The vulnerability does not require user interaction, but it does require local privileges (low privileges) and physical access to the device. The CVSS v4.0 score is 1.0, indicating a low severity level, primarily because of the high complexity and limited scope of impact. The vendor, Signal, was contacted early about this issue but has not responded or issued a patch, and no known exploits are currently observed in the wild. The vulnerability could potentially allow an attacker to bypass biometric authentication, undermining the confidentiality and integrity of the user's communications and data within the Signal app. However, the lack of remote exploitability and the requirement for physical device access significantly limit the threat's scope and impact.

For European organizations, the impact of CVE-2025-5715 is relatively limited due to the requirement of physical access and the high complexity of exploitation. However, Signal is widely used for secure communications, including by journalists, activists, and professionals handling sensitive information. A successful bypass of biometric authentication could lead to unauthorized access to private communications, potentially exposing confidential organizational data or personal information. This could have reputational consequences and may violate data protection regulations such as GDPR if personal data is compromised. The threat is more pronounced in environments where devices are at risk of theft or unauthorized physical access, such as in public or insecure workspaces. Since Signal is often used for end-to-end encrypted messaging, any compromise of device-level authentication could undermine trust in secure communications within European entities relying on the app for privacy.

Given the absence of an official patch from the vendor, European organizations and users should adopt specific mitigation strategies beyond generic advice: 1) Enforce strict physical security controls to prevent unauthorized access to devices running Signal, including secure storage and use of device locks. 2) Encourage users to update Signal promptly once a patched version is released; meanwhile, consider temporarily limiting the use of biometric authentication within the app if possible, or disable biometric unlock features at the OS level. 3) Implement device management policies that restrict installation of vulnerable app versions and monitor for unauthorized device access attempts. 4) Educate users about the risks of physical device compromise and promote the use of strong passcodes or PINs as an additional authentication layer. 5) Consider using additional endpoint security solutions that can detect or prevent unauthorized access attempts on mobile devices. 6) Monitor threat intelligence feeds for any emerging exploit activity related to this CVE to respond swiftly if exploitation in the wild is detected.