What’s Vulnerable › Vulnerabilities

CVE-2026-26164: M365 Copilot Information Disclosure Vulnerability

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-05-07 · updated 2026-10-26
• Weakness: CWE-74

Description

Improper neutralization of special elements used in a command ('command injection') in M365 Copilot allows an unauthorized attacker to disclose information over a network.

Affected products

• Microsoft 365 Copilot's Business Chat: all versions
• Microsoft 365 Copilot's Business Chat: all versions

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-26164

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