CVE-2026-21535: CWE-284: Improper Access Control in Microsoft Microsoft Teams
Improper access control in Microsoft Teams allows an unauthorized attacker to disclose information over a network.
AI Analysis
Technical Summary
CVE-2026-21535 is an improper access control vulnerability (CWE-284) in Microsoft Teams that enables unauthorized attackers to disclose sensitive information over a network. The vulnerability has a CVSS 3.1 base score of 8.2, indicating high severity, with network attack vector, low attack complexity, no privileges required, and no user interaction needed. Microsoft has published an official fix for this vulnerability, as documented in their security update guide.
Potential Impact
Successful exploitation of this vulnerability can lead to unauthorized disclosure of information, impacting confidentiality. The integrity impact is low, and availability is not affected. There are no known active exploits in the wild.
Mitigation Recommendations
An official fix is available from Microsoft. Users and administrators should apply the security update provided in the Microsoft advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21535 to remediate this vulnerability.
CVE-2026-21535: CWE-284: Improper Access Control in Microsoft Microsoft Teams
Description
Improper access control in Microsoft Teams allows an unauthorized attacker to disclose information over a network.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-21535 is an improper access control vulnerability (CWE-284) in Microsoft Teams that enables unauthorized attackers to disclose sensitive information over a network. The vulnerability has a CVSS 3.1 base score of 8.2, indicating high severity, with network attack vector, low attack complexity, no privileges required, and no user interaction needed. Microsoft has published an official fix for this vulnerability, as documented in their security update guide.
Potential Impact
Successful exploitation of this vulnerability can lead to unauthorized disclosure of information, impacting confidentiality. The integrity impact is low, and availability is not affected. There are no known active exploits in the wild.
Mitigation Recommendations
An official fix is available from Microsoft. Users and administrators should apply the security update provided in the Microsoft advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21535 to remediate this vulnerability.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- microsoft
- Date Reserved
- 2025-12-30T18:10:54.847Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- official-fix
- Vendor Advisory Urls
- [{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21535","vendor":"Microsoft"}]
Threat ID: 699812ae2c4d84f260aeb027
Added to database: 2/20/2026, 7:52:14 AM
Last enriched: 5/12/2026, 5:16:18 AM
Last updated: 5/22/2026, 4:49:27 PM
Views: 435
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