Microsoft has disclosed a critical remote code execution vulnerability in Microsoft Teams that could allow attackers to execute malicious code and potentially access, modify, or delete user messages.
The vulnerability, tracked as CVE-2025-53783, was published on August 12, 2025, and carries a CVSS severity score of 7.5, classified as “Important” by Microsoft’s security response team.
Technical Details and Attack Vector
The vulnerability stems from a heap-based buffer overflow weakness (CWE-122) within Microsoft Teams’ code execution framework.
This type of flaw occurs when a program writes more data to a buffer than it can hold, potentially overwriting adjacent memory locations and enabling attackers to inject and execute arbitrary code.
| Field | Value |
|---|---|
| CVE ID | CVE-2025-53783 |
| Release Date | August 12, 2025 |
| Assigning CNA | Microsoft |
| Vulnerability Type | Remote Code Execution |
| Maximum Severity | Important |
| Weakness Classification | CWE-122: Heap-based Buffer Overflow |
According to the Common Vulnerability Scoring System (CVSS) assessment, the attack vector operates over a network connection with high attack complexity, meaning exploitation requires sophisticated technical knowledge and specific conditions to be successful.
The vulnerability requires no special privileges to exploit, but it does necessitate user interaction, suggesting that potential victims would need to perform some action, such as clicking a malicious link or opening a compromised file, to trigger the exploit.
The CVSS metrics indicate that successful exploitation could result in high impact across all three security pillars: confidentiality, integrity, and availability.
This means attackers could potentially read sensitive communications, modify existing messages or data, and disrupt Teams functionality for affected users.
Despite the serious potential impact, Microsoft’s exploitability assessment rates this vulnerability as “Exploitation Less Likely.”
This assessment considers factors such as the complexity required to develop working exploit code and the specific conditions needed for successful attacks.
Currently, there are no reports of public disclosure of exploit code, nor any evidence of active exploitation in the wild.
The vulnerability’s network-based attack vector means that remote attackers could potentially target victims without requiring physical access to their devices.
However, the high attack complexity and user interaction requirements serve as natural barriers that may limit widespread exploitation attempts.
Microsoft has released an official fix for CVE-2025-53783, and organizations using Microsoft Teams should prioritize applying security updates immediately.
The availability of an official remediation solution significantly reduces the long-term risk associated with this vulnerability.
IT administrators should implement standard security practices including keeping Teams applications updated, educating users about suspicious links and attachments, and monitoring for unusual network activity.
Given Teams’ widespread use in corporate environments, this vulnerability could pose particular risks to business communications and sensitive corporate data.
Organizations should also review their incident response procedures and ensure they have appropriate backup and recovery systems in place to mitigate potential data integrity issues should an attack occur.
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