CVE-2025-53783: 
NixOS vulnerability analysis and mitigation

CVE-2025-53783 is a heap-based buffer overflow vulnerability in Microsoft Teams that allows an unauthorized remote attacker to execute arbitrary code over a network. It was disclosed and patched on August 12, 2025, as part of Microsoft's August 2025 Patch Tuesday release. Affected products include Microsoft Teams for Desktop (before 25122.1415.3698.6812), Teams for macOS (before 25122.1207.3700.1444), Teams for Android (before 1.0.0.2025102802), Teams for iOS (before 7.10.1), Teams Phones (before 1.0.94.2025168802), Teams Panels (before 1.0.97.2025102203), Dynamics 365 Remote Assist for HoloLens (before 316.2505.28001), and Dynamics 365 Guides for HoloLens (before 907.2505.29001.0). The vulnerability carries a CVSS v3.1 base score of 7.5 (High) (Microsoft MSRC, Feedly).

The vulnerability is classified as CWE-122 (Heap-based Buffer Overflow), where improper memory management in Microsoft Teams allows an attacker to write beyond the bounds of a heap-allocated buffer, potentially enabling arbitrary code execution. The attack vector is network-based with high attack complexity and requires user interaction (UI:R), meaning a victim must take some action — such as opening a malicious message or joining a crafted call — to trigger the overflow. No privileges are required on the part of the attacker. A public proof-of-concept has been published on GitHub, though detailed technical write-ups of the specific vulnerable component have not been widely released (Microsoft MSRC, ZDI Advisory).

Successful exploitation grants an attacker remote code execution on the affected system with the privileges of the Teams application user, resulting in high impact to confidentiality, integrity, and availability. An attacker could read, modify, or delete messages and files, access sensitive organizational communications, and potentially pivot to other systems accessible from the compromised endpoint. The broad deployment of Microsoft Teams across enterprise environments significantly amplifies the potential blast radius of exploitation (Microsoft MSRC, Feedly).

A public proof-of-concept exploit has been published on GitHub at https://github.com/ksgassama-lab/MSTeams---Vulnerability---Remediation, added to tracking on March 2, 2026. As of the time of reporting, there is no confirmed evidence of active in-the-wild exploitation, and the vulnerability has not been added to CISA's Known Exploited Vulnerabilities (KEV) catalog. The EPSS score is approximately 0.055%, reflecting a currently low but non-negligible probability of exploitation. The vulnerability is detectable via Nessus (plugin 250276) and Qualys (QID 384352) (Feedly, ZDI Advisory).

1. Reconnaissance: Identify target organizations using Microsoft Teams by reviewing public information, LinkedIn profiles, or job postings indicating Teams usage. Enumerate potential victim users via organizational directories or social engineering.
2. Craft malicious payload: Develop or adapt a heap overflow payload targeting the vulnerable Teams component, leveraging the public PoC as a reference (https://github.com/ksgassama-lab/MSTeams---Vulnerability---Remediation).
3. Deliver payload: Send the malicious content to the victim via a Teams message, meeting invitation, or other in-app communication channel that triggers the vulnerable code path upon interaction.
4. Trigger user interaction: Wait for or socially engineer the victim to open the malicious message, join a crafted call, or otherwise interact with the payload-bearing content.
5. Achieve code execution: The heap overflow is triggered, allowing the attacker to overwrite heap metadata or function pointers and redirect execution flow, resulting in arbitrary code execution under the context of the Teams process (Microsoft MSRC, ZDI Advisory).

• Network: Unexpected outbound connections from the Teams process (Teams.exe, msedgewebview2.exe) to unknown or suspicious IP addresses or domains following receipt of a Teams message or call.
• Process: Unusual child processes spawned by the Teams application (e.g., cmd.exe, powershell.exe, curl.exe) that are not typical of normal Teams operation.
• Logs: Teams application crash logs or Windows Event Log entries (Application log) indicating heap corruption or access violations in the Teams process around the time of suspicious message receipt.
• File System: Unexpected files written to the Teams application data directory (%AppData%\Microsoft\Teams) or temporary directories by the Teams process, including scripts or executables.
• Memory: Evidence of heap spray or memory corruption artifacts in process memory dumps of the Teams application.

Microsoft released patches on August 12, 2025, for all affected products. Organizations should update to the following minimum versions: Teams Desktop ≥ 25122.1415.3698.6812, Teams for macOS ≥ 25122.1207.3700.1444, Teams for Android ≥ 1.0.0.2025102802, Teams for iOS ≥ 7.10.1, Teams Phones ≥ 1.0.94.2025168802, Teams Panels ≥ 1.0.97.2025102203, Dynamics 365 Remote Assist for HoloLens ≥ 316.2505.28001, and Dynamics 365 Guides for HoloLens ≥ 907.2505.29001.0. Teams typically auto-updates, but administrators should verify update status across all endpoints, particularly for managed devices and specialized hardware. Given the existence of a public PoC, timely patching is strongly recommended (Microsoft MSRC, Feedly).

The vulnerability received notable coverage as part of Microsoft's August 2025 Patch Tuesday, which addressed 107 flaws including one zero-day. Zero Day Initiative published an advisory (ZDI-25-839) and reviewed the update in their August 2025 Security Update Review. Sophos News highlighted the patch in their August Patch Tuesday coverage. Multiple security news outlets including BleepingComputer, CyberSecurityNews, and The Cyber Express covered the RCE risk, with some noting the potential for attackers to read, modify, and delete Teams messages. Rapid7 and Qualys also included the vulnerability in their Patch Tuesday analyses (BleepingComputer, ZDI Advisory, Sophos News, Rapid7).