CVE-2025-29805: Microsoft Outlook Information Disclosure

CVE-2025-29805 Overview

CVE-2025-29805 is an information disclosure vulnerability affecting Microsoft Outlook for Android. The vulnerability allows an unauthorized attacker to disclose sensitive information over a network without requiring authentication or user interaction. This weakness is classified under CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor), indicating improper handling of confidential data within the application.

Critical Impact

Unauthorized network-based attackers can access sensitive user information from Outlook for Android without authentication, potentially exposing emails, contacts, calendar data, or other confidential communications.

Affected Products

• Microsoft Outlook for Android (all versions prior to patch)
• Microsoft Outlook mobile application on Android devices

Discovery Timeline

• 2025-04-08 - CVE-2025-29805 published to NVD
• 2025-07-10 - Last updated in NVD database

Technical Details for CVE-2025-29805

Vulnerability Analysis

This vulnerability represents an information disclosure flaw in Microsoft Outlook for Android that enables unauthorized actors to extract sensitive data over a network connection. The vulnerability requires no privileges or user interaction to exploit, making it particularly dangerous in enterprise environments where mobile devices frequently connect to untrusted networks.

The attack can be conducted remotely over a network with low complexity, meaning attackers do not need specialized access or sophisticated techniques to exploit this weakness. The confidentiality impact is significant as sensitive email data, authentication tokens, or other personal information stored within the Outlook application may be exposed.

Root Cause

The root cause stems from improper information exposure (CWE-200) within the Outlook for Android application. The application fails to adequately protect sensitive data during network communications or data handling operations, allowing unauthorized actors to intercept or access confidential information that should remain protected.

Attack Vector

The attack vector is network-based, allowing remote exploitation without physical access to the target device. An attacker positioned on the same network or with the ability to intercept network traffic could potentially exploit this vulnerability to extract sensitive information from the Outlook application.

The vulnerability characteristics indicate that exploitation does not require any special privileges on the target system, and no user interaction is necessary. This means the attack can be conducted silently without alerting the user, making detection particularly challenging.

Detection Methods for CVE-2025-29805

Indicators of Compromise

• Unusual network traffic patterns originating from the Outlook for Android application
• Unexpected data exfiltration to unknown external IP addresses
• Anomalous API calls or network requests from the Outlook mobile application
• Evidence of sensitive data transmission over unencrypted channels

Detection Strategies

• Monitor mobile device network traffic for suspicious outbound connections from the Outlook application
• Implement network-level inspection to detect potential data leakage patterns
• Deploy mobile threat defense (MTD) solutions to identify anomalous application behavior
• Review application logs for unexpected data access patterns

Monitoring Recommendations

• Enable detailed logging for enterprise mobility management (EMM) solutions
• Configure network monitoring to alert on unusual Outlook for Android traffic patterns
• Implement data loss prevention (DLP) policies to detect sensitive information exposure
• Regularly audit mobile application versions across the organization

How to Mitigate CVE-2025-29805

Immediate Actions Required

• Update Microsoft Outlook for Android to the latest available version immediately
• Enforce application updates through enterprise mobility management (EMM) policies
• Review network security configurations for mobile device access
• Assess whether sensitive data may have been exposed prior to patching

Patch Information

Microsoft has released a security update addressing this vulnerability. Organizations should apply the patch as soon as possible through the Google Play Store or enterprise application distribution mechanisms. Detailed patch information is available in the Microsoft Security Advisory.

Workarounds

• Restrict Outlook for Android access to trusted networks only until patching is complete
• Implement network segmentation to limit exposure of mobile devices
• Consider temporarily using alternative email clients if immediate patching is not possible
• Enable additional authentication controls such as conditional access policies

# Enterprise MDM policy enforcement example
# Require minimum Outlook version with security patch
# Configure in your EMM/MDM console:
# - Set minimum app version requirement for Microsoft Outlook
# - Enable automatic app updates
# - Block access for non-compliant devices