CVE-2026-47645: Microsoft 365 Copilot's Business Chat Elevation of Privilege Vulnerability

highCVSS 8.8CVE-2026-47645

Url redirection to untrusted site ('open redirect') in Microsoft 365 Copilot's Business Chat allows an unauthorized attacker to elevate privileges over a network.

CSIRTS triage

vendor: Microsoft product: Microsoft 365 Copilot Authentication bypass

What: An open redirect vulnerability allows unauthorized privilege elevation.
Who is affected: Users of Microsoft 365 Copilot's Business Chat are affected.
Urgency: High urgency for remediation due to the potential for privilege escalation and a CVSS score of 8.8.
Action: Apply the latest security updates to Microsoft 365 Copilot.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: high — CVSS 8.8
Published: 2026-06-09
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-47645

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-476450.41% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 33% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-47645	coverage & exploitation status	NVD · CVE.org

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