CRITICAL

CVE-2026-50517

CVSS v3

9.9

CRITICAL

EPSS Score

1.3%

exploit probability

CISA KEV

No

known exploited

Exploitation

SSVC status

Description

Deserialization of untrusted data in M365 Copilot allows an authorized attacker to execute code over a network.

Technical details

CVSS v3 Vector
3.1
Published
7/24/2026
Last Modified
7/24/2026

Frequently asked questions

What is CVE-2026-50517?

Deserialization of untrusted data in M365 Copilot allows an authorized attacker to execute code over a network.

Is CVE-2026-50517 actively exploited?

Active exploitation of CVE-2026-50517 has not been confirmed. The EPSS score is 1.3%, indicating the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-50517?

CVE-2026-50517 has a CVSS v3 base score of 9.9 (CRITICAL severity), with vector string 3.1.

Is CVE-2026-50517 affecting your environment?

Use isMalicious to check if any of your IPs or domains are associated with this vulnerability's IOCs.