Is CVE-2026-50517 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-50517 being exploited in the wild.

How severe is CVE-2026-50517?

Critical severity, with a CVSS score of 9.9, published 24 July 2026.

Which products and versions are affected?

Microsoft Copilot for Microsoft 365 All versions.

Is there a fix for CVE-2026-50517?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-50517 attacked?

It is attacked over the network, in a hosted service.

Am I affected by CVE-2026-50517?

Check whether you run Microsoft Copilot for Microsoft 365 at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-50517: Microsoft 365 Copilot deserialization of untrusted data

CVE-2026-50517 · Severity: critical · CVSS 9.9 · Published 2026-07-24

Microsoft 365 Copilot, an AI-powered productivity tool, contains a critical security flaw that could allow an authorized user to execute unauthorized commands. An attacker with basic access to the service could potentially take full control of the environment, leading to significant data theft or service disruption. Because this is a cloud-based service, Microsoft typically manages the necessary updates to resolve the issue.

Vendors: Microsoft.

Quick answers

Is CVE-2026-50517 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-50517 being exploited in the wild.
How severe is CVE-2026-50517?: Critical severity, with a CVSS score of 9.9, published 24 July 2026.
Which products and versions are affected?: Microsoft Copilot for Microsoft 365 All versions.
Is there a fix for CVE-2026-50517?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-50517 attacked?: It is attacked over the network, in a hosted service.
Am I affected by CVE-2026-50517?: Check whether you run Microsoft Copilot for Microsoft 365 at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A deserialization vulnerability (CWE-502) exists in Microsoft 365 Copilot due to the insecure handling of untrusted data. An attacker with low-privileged network access can exploit this flaw without any user interaction to achieve remote code execution. The vulnerability is particularly severe as it carries a 'Changed' Scope (S:C) in the CVSS metric, indicating that an exploit could impact components beyond the immediate security scope of the Copilot service. As an exclusively hosted service, remediation is primarily handled by Microsoft on the backend.

Affected products

Microsoft Microsoft 365 Copilot All versions

Timeline

2026-07-24: disclosed: Initial advisory publication date
2026-07-24: advisory: Microsoft and NVD published vulnerability details

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50517

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.