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Privacy Statement Third-Party Cookies AcceptRejectManage cookies MSRC  Customer Guidance  Security Update Guide  Vulnerabilities  CVE-2026-69375 Microsoft Exchange Server Tampering Vulnerability New On this page  CVE-2026-69375  Subscribe RSS PowerShell  API  CSAF Security Vulnerability Released: Sep 8, 2026 Assigning CNA Microsoft CVE.org link CVE-2026-69375  Impact Tampering Max Severity Important Weakness CWE-639: Authorization Bypass Through User-Controlled Key CVSS Source Microsoft Vector String CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N/E:U/RL:O/RC:C Metrics CVSS:3.1 6.5 / 5.7  Base score metrics: 6.5 / Temporal score metrics: 5.7  Expand all  Collapse all Metric Value   Base score metrics(8) Attack Vector Network Attack Complexity Low Privileges Required Low User Interaction None Scope Unchanged Confidentiality None Integrity High Availability None   Temporal score metrics(3) Exploit Code Maturity Unproven Remediation Level Official Fix Report Confidence Confirmed Please see Common Vulnerability Scoring System for more information on the definition of these metrics. Executive Summary Authorization bypass through user-controlled key in Microsoft Exchange Server allows an authorized attacker to perform tampering over a network. Exploitability The following table provides an exploitability assessment for this vulnerability at the time of original publication. Publicly disclosed No Exploited No Exploitability assessment Exploitation Less Likely FAQ According to the CVSS metrics, successful exploitation of this vulnerability could lead to major loss of integrity (I:H). What does that mean for this vulnerability? An authenticated attacker could replace valid file content with specially crafted file content. According to the CVSS metric, privileges required is low (PR:L). What does that mean for this vulnerability? Any authenticated attacker could trigger this vulnerability. It does not require admin or other elevated privileges. Acknowledgements  John Nzyuko Microsoft recognizes the efforts of those in the security community who help us protect customers through coordinated vulnerability disclosure. See Acknowledgements for more information. Security Updates To determine the support lifecycle for your software, see the Microsoft Support Lifecycle. Release date Descending  Edit columns  Download  Filters  Product Family  Max Severity  Impact  Platform   Clear Release date  Product Platform Impact Max Severity Article Download Build Number Assigning CNA Title: Release date, Content: Sep 8, 2026 Microsoft Exchange Server 2019 Cumulative Update 14 - Tampering Important Title: Knowledge Base Articles for Microsoft Exchange Server 2019 Cumulative Update 14, Content:, 1 link 5121610  Title: Download Security Update for Microsoft Exchange Server 2019 Cumulative Update 14, Content:, 1 link Security Update Title: Build numbers, Content: 15.02.1544.046 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Sep 8, 2026 Microsoft Exchange Server 2019 Cumulative Update 15 - Tampering Important Title: Knowledge Base Articles for Microsoft Exchange Server 2019 Cumulative Update 15, Content:, 1 link 5121609  Title: Download Security Update for Microsoft Exchange Server 2019 Cumulative Update 15, Content:, 1 link Security Update Title: Build numbers, Content: 15.02.1748.051 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Sep 8, 2026 Microsoft Exchange Server 2016 Cumulative Update 23 - Tampering Important Title: Knowledge Base Articles for Microsoft Exchange Server 2016 Cumulative Update 23, Content:, 1 link 5121611  Title: Download Security Update for Microsoft Exchange Server 2016 Cumulative Update 23, Content:, 1 link Security Update Title: Build numbers, Content: 15.01.2507.073 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Sep 8, 2026 Microsoft Exchange Server Subscription Edition RTM - Tampering Important Title: Knowledge Base Articles for Microsoft Exchange Server Subscription Edition RTM, Content:, 1 link 5121608  Title: Download Security Update for Microsoft Exchange Server Subscription Edition RTM, Content:, 1 link Security Update  Title: Build numbers, Content: 15.02.2562.049 Title: Assigning CNA, Content: Microsoft All results loaded Loaded all 4 rows Disclaimer The information provided in the Microsoft Knowledge Base is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply. Revisions version revisionDate description 1.0 Sep 8, 2026 Information published.  How satisfied are you with the MSRC Security Update Guide? Rating  Broken  Bad  Below average  Average  Great!  Your Privacy Choices Consumer Health Privacy Privacy & Cookies