CVE-2026-47645
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedUrl redirection to untrusted site ('open redirect') in Microsoft 365 Copilot's Business Chat allows an unauthorized attacker to elevate privileges over a network.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceOpen redirect vulnerability in Microsoft 365 Copilot's Business Chat component allows attackers to craft malicious URLs that redirect users to untrusted external sites. This URL redirection flaw can be chained with other techniques to perform privilege elevation attacks over a network, enabling unauthorized actors to potentially escalate their access privileges.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE dataall versionsCVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Confirm Microsoft 365 Copilot deploymentReview your Microsoft 365 admin center or Azure AD portal to list users or groups with Copilot licenses assigned. Use PowerShell with Get-MsolAccountSku or Microsoft Graph API to enumerate Copilot-enabled tenants.Affected if Any user or group has Microsoft 365 Copilot licenses assigned in the tenant.
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Identify Business Chat usageCheck for access to the Copilot Business Chat feature, typically accessed via copilot.microsoft.com or within Microsoft 365 apps (Teams, Outlook, Office.com). Review user activity logs in Microsoft 365 admin center under Copilot usage reports.Affected if Business Chat component is accessible to any user in the organization.
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Monitor for suspicious redirect URLsInspect Microsoft 365 audit logs (Search-MailboxAuditLog or Purview compliance portal) for Copilot-related sign-in events and URL patterns. Look for outbound redirects in Copilot responses using Microsoft Graph API or network proxy logs filtering for copilot.microsoft.com domains.Affected if Logs show HTTP 3xx responses from Copilot endpoints redirecting to external non-Microsoft domains.
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Review network perimeter logsExamine proxy, firewall, or CASB (Cloud Access Security Broker) logs for outbound connections from Copilot-associated IP addresses or user agents to untrusted external domains. Correlate with Copilot session timestamps.Affected if Network logs capture redirects from Copilot endpoints to domains not in your organization's allowlist.
If Microsoft 365 Copilot with Business Chat is enabled for any user in your organization, you are affected by this open redirect vulnerability since all versions are impacted.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataMonitor Microsoft's official security advisories and cumulative updates for Microsoft 365 Copilot; apply vendor-provided patches promptly. Implement URL validation and filtering at the network perimeter for Copilot-related domains until the vulnerability is remediated by Microsoft.
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- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-47645 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-47645 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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