CVE-2026-50517: CWE-502: Deserialization of Untrusted Data in Microsoft Microsoft 365 Copilot
CVE-2026-50517 is a critical vulnerability in Microsoft 365 Copilot involving deserialization of untrusted data. This flaw allows an authorized attacker to execute code remotely over a network without user interaction. The vulnerability has a CVSS score of 9.9, indicating a severe impact on confidentiality, integrity, and availability. Microsoft has issued an official fix for this cloud service vulnerability.
AI Analysis
Technical Summary
This vulnerability (CWE-502) in Microsoft 365 Copilot arises from improper deserialization of untrusted data, enabling an authorized attacker to execute arbitrary code remotely. The vulnerability is remotely exploitable with low attack complexity and no user interaction required. It affects the cloud-hosted Microsoft 365 Copilot service. Microsoft has released an official fix and manages remediation server-side for this cloud service.
Potential Impact
Successful exploitation can lead to complete compromise of the Microsoft 365 Copilot environment, including full confidentiality, integrity, and availability impacts. The attacker can execute arbitrary code remotely, potentially leading to data breaches, service disruption, or further network compromise.
Mitigation Recommendations
Microsoft has provided an official fix for this vulnerability and manages remediation for the cloud-hosted Microsoft 365 Copilot service. Users should ensure their Microsoft 365 Copilot service is updated according to Microsoft's guidance available at the official advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50517
CVE-2026-50517: CWE-502: Deserialization of Untrusted Data in Microsoft Microsoft 365 Copilot
Description
CVE-2026-50517 is a critical vulnerability in Microsoft 365 Copilot involving deserialization of untrusted data. This flaw allows an authorized attacker to execute code remotely over a network without user interaction. The vulnerability has a CVSS score of 9.9, indicating a severe impact on confidentiality, integrity, and availability. Microsoft has issued an official fix for this cloud service vulnerability.
CVSS v3.1
Score 9.9critical
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability (CWE-502) in Microsoft 365 Copilot arises from improper deserialization of untrusted data, enabling an authorized attacker to execute arbitrary code remotely. The vulnerability is remotely exploitable with low attack complexity and no user interaction required. It affects the cloud-hosted Microsoft 365 Copilot service. Microsoft has released an official fix and manages remediation server-side for this cloud service.
Potential Impact
Successful exploitation can lead to complete compromise of the Microsoft 365 Copilot environment, including full confidentiality, integrity, and availability impacts. The attacker can execute arbitrary code remotely, potentially leading to data breaches, service disruption, or further network compromise.
Mitigation Recommendations
Microsoft has provided an official fix for this vulnerability and manages remediation for the cloud-hosted Microsoft 365 Copilot service. Users should ensure their Microsoft 365 Copilot service is updated according to Microsoft's guidance available at the official advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50517
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- microsoft
- Date Reserved
- 2026-06-04T19:00:41.292Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- official-fix
- Is Cloud Service
- true
- Vendor Advisory Urls
- [{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50517","vendor":"Microsoft"}]
Threat ID: 6a62b3ff9c2644c7f8000d4b
Added to database: 07/24/2026, 00:38:23 UTC
Last enriched: 07/24/2026, 00:52:37 UTC
Last updated: 07/24/2026, 03:48:27 UTC
Views: 8
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