CVE-2025-29805 is a high-severity vulnerability identified in Microsoft Outlook for Android version 1.0. The vulnerability is categorized under CWE-200, which pertains to the exposure of sensitive information to unauthorized actors. Specifically, this flaw allows an attacker to disclose sensitive information over a network without requiring any privileges or user interaction. The CVSS 3.1 base score of 7.5 reflects a significant risk, with an attack vector classified as network-based (AV:N), low attack complexity (AC:L), no privileges required (PR:N), and no user interaction needed (UI:N). The scope remains unchanged (S:U), but the confidentiality impact is high (C:H), while integrity and availability impacts are none (I:N, A:N). This means that an attacker can remotely access sensitive data transmitted or stored by the vulnerable Outlook for Android app without altering or disrupting the service. The vulnerability affects only version 1.0 of the app, and as of the publication date, no known exploits have been reported in the wild. The lack of available patches at the time of disclosure indicates that users remain exposed until Microsoft releases an update. The technical details confirm the vulnerability was reserved in early March 2025 and published in April 2025, with enrichment from CISA, suggesting recognition by US cybersecurity authorities. Overall, this vulnerability represents a critical privacy risk for users of Outlook on Android devices, potentially exposing emails or related sensitive information to interception or unauthorized disclosure over the network.

For European organizations, the exposure of sensitive information through Microsoft Outlook for Android can have severe consequences. Outlook is widely used in corporate environments for email communication, calendar management, and collaboration. The vulnerability could lead to unauthorized disclosure of confidential emails, attachments, or calendar data, potentially including personally identifiable information (PII), intellectual property, or strategic business communications. This exposure risks violating the EU's General Data Protection Regulation (GDPR), which mandates strict controls on personal data confidentiality and imposes heavy fines for breaches. Additionally, the loss of sensitive business information could damage corporate reputation, enable corporate espionage, or facilitate further targeted attacks such as phishing or social engineering. Since the vulnerability requires no authentication or user interaction, attackers could exploit it remotely and stealthily, increasing the risk of widespread data leakage. The impact is particularly critical for sectors handling sensitive data such as finance, healthcare, government, and critical infrastructure within Europe.

To mitigate this vulnerability, European organizations should immediately assess the deployment of Microsoft Outlook for Android version 1.0 within their environment. Until an official patch is released by Microsoft, organizations should consider the following specific actions: 1) Temporarily restrict or disable the use of Outlook for Android 1.0 on corporate-managed devices, especially for users handling sensitive or regulated data. 2) Implement network-level controls such as segmentation and monitoring to detect unusual data exfiltration patterns from mobile devices. 3) Enforce the use of virtual private networks (VPNs) with strong encryption to protect data in transit from interception. 4) Educate users about the risk and encourage the use of alternative secure email clients or web-based Outlook access on trusted devices. 5) Monitor threat intelligence feeds and Microsoft advisories closely for the release of patches or workarounds. 6) Employ mobile device management (MDM) solutions to enforce app version controls and remotely remove or update vulnerable applications. 7) Conduct regular audits of mobile device configurations and network traffic to identify potential exploitation attempts. These targeted measures go beyond generic advice by focusing on controlling app usage, network protections, and proactive monitoring tailored to this specific vulnerability.