(Updated) Important Update: Teams Meeting Join URL Validation [MC1120871]

Message ID: MC1120871 (Updated)

Updated August 6, 2025: We have updated this message with additional information to clarify the Meeting joins experience. Thank you for your patience.

What and Who

To enhance the security and integrity of Microsoft Teams meetings, we are introducing a new feature that validates Teams meeting join URLs. This update helps ensure that meeting links are not altered or rewritten by security products in ways that could render them unusable or flagged as malicious.

Rollout Schedule

• Worldwide: September 30, 2025
• GCC, GCC High, DoD: November 30, 2025

Impact on Your Organization

• Who is affected:
  • Organizations using security products that inspect or rewrite URLs, and users who join Microsoft Teams meetings via meeting links.

• What will happen:
  • Microsoft Teams will validate join URLs to ensure they have not been modified.
  • If a join URL is rewritten or altered by a security product, it may be marked as malicious.
  • Users may be prevented from joining meetings if URLs are not in their original format.
  • This feature is enabled by default and does not require admin configuration.

Note: Meeting joins will only be blocked if the join links are re-written in the calendar event details (Join URL). If the links are only re-written in the meeting description (or meeting body), it won’t impact the ability to join.

Action Required/Recommendations

• Ensure that your security products do not rewrite Microsoft Teams meeting join URLs.
• Whitelist Microsoft Teams join URLs in your security software.
• Review your organization’s URL rewriting or inspection policies before the rollout date.
• Communicate this change to your helpdesk and security teams.

Compliance Considerations

No compliance considerations identified, review as appropriate for your organization.

Source: Microsoft

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