Cyber Resilience

CVE-2026-47645

Open Redirect in Microsoft 365 Copilot

Open Redirect
Published
19 June 2026
Modified
26 June 2026
Patch / advisory
View advisory
CVSS Score v3.1 8.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS Score 0.0076 52th percentile
Risk Priority 65 floored blend · peak EPSS

Summary

CVE-2026-47645 is a high-severity Open Redirect (CWE-601) vulnerability in Microsoft 365 Copilot. Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Phishing (T1566); ranked in the top 48% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

This vulnerability is AI-related — categorised as Enterprise AI Assistants.

The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) and AC-4 (Information Flow Enforcement) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A01:2025 Broken Access Control

EU & UK References

Vulnerability Data

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

CWE(s)
CWE-601

AI Security AnalysisAI

AI Category
Enterprise AI Assistants
Risk Domain
N/A
OWASP Top 10 for LLMs 2025
None mapped
Classification Reason
Matched keywords: copilot

Related Threats

MITRE ATT&CK Enterprise Techniques

T1566 Phishing Initial Access
Adversaries may send phishing messages to gain access to victim systems.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-33102Same product: Microsoft 365 Copilot
CVE-2026-41106Same product: Microsoft 365 Copilot
CVE-2025-21401Same vendor: Microsoft
CVE-2024-43536Same vendor: Microsoft
CVE-2023-23395Same vendor: Microsoft
CVE-2024-43543Same vendor: Microsoft
CVE-2023-23391Same product: Microsoft 365 Copilot
CVE-2023-25734Same vendor: Microsoft
CVE-2026-24052Shared CWE-601
CVE-2023-20884Same vendor: Microsoft

Affected Assets

microsoft
365 copilot
all versions

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V3.7.2

Mitigating Controls (NIST 800-53 r5) AI

SI-10 Information Input Validation good match

Input validation directly checks and rejects untrusted redirect targets before they are used in a response.

AC-4 Information Flow Enforcement partial match

Information flow enforcement can restrict redirects to only approved/trusted destinations, stopping untrusted user-supplied URLs from being followed.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require input validation and untrusted-redirect controls that prevent CWE-601.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.23 Web filtering partial match
mitigates

Preventing access to attacker-controlled or malicious sites stops users from being redirected to untrusted locations via open-redirect or phishing links.

References