Microsoft disclosed a significant remote code execution (RCE) vulnerability in its Teams collaboration software as part of its August 2025 Patch Tuesday updates.
The critical flaw, identified as CVE-2025-53783, could allow an unauthorized attacker to read, write, and even delete user messages and data by executing code over a network.
The vulnerability is a heap-based buffer overflow, a type of memory corruption weakness where an application can be forced to store data beyond the allocated memory space on the heap.
An attacker could exploit this flaw to overwrite critical data or execute malicious code within the context of the Teams application.
According to Microsoft, a successful exploit could have a high impact on the confidentiality, integrity, and availability of a user’s data, granting the attacker privileges to read, write, and delete information.
Microsoft has assigned the vulnerability a CVSS 3.1 score of 7.5, rating its severity as “Important.” The company notes that exploiting this flaw has a high degree of complexity (AC: H), requiring an attacker to gather specific information about the target’s environment.
Microsoft Teams RCE Vulnerability
Furthermore, user interaction is required for a successful attack, meaning a target would likely need to click a malicious link or open a specially crafted file.
As of the announcement, the vulnerability has not been publicly disclosed or actively exploited. Microsoft’s exploitability assessment indicates that exploitation is “Less Likely.”
The company has already issued an official fix and is urging users and administrators to apply the latest security updates to mitigate the risk.
This Teams vulnerability was one of 107 flaws addressed in this month’s Patch Tuesday release, which also included a fix for a publicly disclosed zero-day vulnerability in Windows Kerberos.
The extensive monthly patch is a reminder of the persistent security challenges facing major enterprise software platforms. In recent months, Microsoft has also contended with significant vulnerabilities in its SharePoint servers, some of which were reported to be actively exploited.
While this specific Teams RCE flaw requires a complex attack chain, past vulnerabilities in enterprise messaging apps have shown the potential for widespread impact.
Similar exploits in platforms like Teams and Slack have, in some cases, been “wormable,” allowing them to spread automatically from one compromised account to an entire organization.
Given the potential for complete data compromise, security experts recommend that all organizations using Microsoft Teams prioritize the deployment of the August 2025 security updates immediately.
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