What is CVE-2026-47645?

CVE-2026-47645 is a high-severity vulnerability in Microsoft 365 Copilot, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 8.8/10. Published 2026-06-19.

How severe is CVE-2026-47645?

High severity. CVSS v3 base score is 8.8 out of 10.

Open Redirect in Microsoft 365 Copilot

CVE-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.

Vulnerability class: Open Redirect

Published 2026-06-19 · last modified 2026-06-26.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.008 (53.5th percentile), scored 2026-10-01.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 53rd percentile — 53.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: 0.000

Affected products

Weakness classification (CWE)

CWE-601 — URL Redirection to Untrusted Site (Open Redirect)

References

Microsoft 365 Copilot's Business Chat Elevation of Privilege Vulnerability (vendor-advisory, patch, Vendor Advisory)

Frequently asked questions

What is CVE-2026-47645?: CVE-2026-47645 is a high-severity vulnerability in Microsoft 365 Copilot, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 8.8/10. Published 2026-06-19.
How severe is CVE-2026-47645?: High severity. CVSS v3 base score is 8.8 out of 10.