CVE-2026-58617 365 copilot vulnerability
Improper access control in Microsoft 365 Copilot for iOS allows an unauthorized attacker to elevate privileges over a network.
Quick answer
microsoft 365 copilot should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- Review vendor advisory for affected versions.
Fixed versions
- Apply the latest vendor-supported patched version.
How to fix it
Improper access control in Microsoft 365 Copilot for iOS allows an unauthorized attacker to elevate privileges over a network. This matters because Microsoft 365 Copilot can touch sensitive work data and user permissions. Apply the Microsoft 365 app or service-side update guidance for the affected iOS client. Also review tenant access, mobile app versions, and audit logs for any unusual activity.
- Identify users and devices that use Microsoft 365 Copilot for iOS and may be in scope for CVE-2026-58617.
- Update the Microsoft 365 Copilot app from the official app store or managed mobile app channel.
- Use Intune or MDM policy to block outdated app versions if possible.
- Review Copilot and Microsoft 365 audit logs for unusual access or permission changes.
- Check conditional access and app protection policies for sensitive accounts.
- Ask affected users to restart the app and sign in again after the update.
- Escalate any suspicious activity for incident review.
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Verify the fix
- Confirm managed devices report the updated Copilot app version.
- Verify that no outdated iOS Copilot clients remain active for CVE-2026-58617.
- Review audit logs for privilege changes, unusual prompts, or unexpected file access.
- Confirm conditional access and MDM controls still apply to Copilot users.
- Save the app version report and audit review notes.
Related categories
Trusted references
FAQ
What is affected by CVE-2026-58617?
microsoft 365 copilot should be checked against the vendor advisory and trusted references linked on this page.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.