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Privacy Statement Third-Party Cookies AcceptRejectManage cookies MSRC  Customer Guidance  Security Update Guide  Vulnerabilities  CVE-2026-70306 Microsoft Office SharePoint Spoofing Vulnerability New On this page  CVE-2026-70306  Subscribe RSS PowerShell  API  CSAF Security Vulnerability Released: Aug 11, 2026 Assigning CNA Microsoft CVE.org link CVE-2026-70306  Impact Spoofing Max Severity Important Weakness CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') CVSS Source Microsoft Vector String CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N/E:U/RL:O/RC:C Metrics CVSS:3.1 9.3 / 8.1  Base score metrics: 9.3 / Temporal score metrics: 8.1  Expand all  Collapse all Metric Value   Base score metrics(8) Attack Vector Network Attack Complexity Low Privileges Required None User Interaction Required Scope Changed Confidentiality High 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 Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Office SharePoint allows an unauthorized attacker to perform spoofing 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 How could an attacker exploit this vulnerability? An attacker could send a specially crafted URL to an authenticated SharePoint user and persuade them to visit it and submit the form. Successful exploitation could allow the attacker to run script in the user's SharePoint session, potentially accessing information or modifying site content. Acknowledgements Jongseong Kim (nevul37) https://nevul37.github.io/ with UIUC Hwiwon Lee (hwiwonl) https://hwiwonl.ee/ with UIUC DongJun Kim https://smlijun.github.io/ with UIUC Bui Xuan Quang (buxu) with Ncsgroup.vn 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: Aug 11, 2026 Microsoft SharePoint Server Subscription Edition - Spoofing Important Title: Knowledge Base Articles for Microsoft SharePoint Server Subscription Edition, Content:, 1 link 5002882  Title: Download Security Update for Microsoft SharePoint Server Subscription Edition, Content:, 1 link Security Update  Title: Build numbers, Content: 16.0.19725.20434 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Aug 11, 2026 Microsoft SharePoint Server 2019 - Spoofing Important Title: Knowledge Base Articles for Microsoft SharePoint Server 2019, Content:, 1 link 5002883  Title: Download Security Update for Microsoft SharePoint Server 2019, Content:, 1 link Security Update  Title: Build numbers, Content: 16.0.10417.20175 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Aug 11, 2026 Microsoft SharePoint Enterprise Server 2016 - Spoofing Important Title: Knowledge Base Articles for Microsoft SharePoint Enterprise Server 2016, Content:, 1 link 5002891  Title: Download Security Update for Microsoft SharePoint Enterprise Server 2016, Content:, 1 link Security Update  Title: Build numbers, Content: 16.0.5561.1001 Title: Assigning CNA, Content: Microsoft All results loaded Loaded all 3 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 Aug 11, 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