CVE-2025-53783: Remote Code Execution Flaw in Microsoft Teams – Patch Now!

On August 12, 2025, Microsoft released details for CVE-2025-53783, a heap-based buffer overflow vulnerability in Microsoft Teams that could allow remote code execution (RCE) without requiring administrative privileges. The vulnerability impacts multiple Teams platforms, including desktop, mobile, and specialized hardware. Although the attack is not easy to execute, the risk remains, especially in corporate environments where social engineering tactics can be effective.

Severity Level: High

Vulnerability Details

• CVE ID: CVE-2025-53783
• CVSS Score: 7.5
• Weakness: CWE-122 – Heap-Based Buffer Overflow
• User Interaction: Required (e.g., clicking a malicious link or opening a file in Teams)
• Exploit Status: No public disclosure or in-the-wild exploitation as of publication.
• The issue results from improper heap memory allocation and bounds checking within Microsoft Teams.

Exploitation Of The Vulnerabilities

An attacker could craft a malicious link, file, or chat message that, when opened or interacted with in Microsoft Teams, triggers the heap overflow. Successful exploitation could allow:

• Reading private Teams conversations
• Modifying or deleting messages
• Executing arbitrary code remotely
• Potential pivoting to other systems within the same network

Given the high attack complexity, exploitation would require reconnaissance of the target environment, making mass exploitation less probable but targeted attacks feasible.

Affected Products

According to Microsoft, the vulnerability affects the following platforms:

• Microsoft Teams for Mac
• Microsoft Teams for Desktop (Windows)
• Microsoft Teams for iOS
• Microsoft Teams for Android
• Teams for Dynamics 365 Guides HoloLens
• Teams for Dynamics 365 Remote Assist HoloLens
• Teams Phones
• Teams Panels

Recommendations

1. Apply the August 2025 Patch Tuesday updates for all the affected Microsoft Teams platforms.
2. Educate users about phishing and malicious file risks in collaboration tools.
3. Restrict file sharing permissions for external participants.
4. Implement conditional access policies requiring MFA for all Teams logins, especially from unmanaged devices.
5. Enforce application control policies (e.g., Windows Defender Application Control, macOS Gatekeeper) to prevent unauthorized executables from running if exploitation occurs.
6. Update incident response playbooks to include Microsoft Teams compromise scenarios.

Source:

• https://thecyberexpress.com/microsoft-teams-cve-2025-53783-rce-flaw/
• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-53783

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