CVE-2025-29976: SharePoint Server Privilege Escalation Flaw

CVE-2025-29976 is a privilege escalation vulnerability in Microsoft SharePoint Server caused by improper privilege management. Authorized attackers can exploit this flaw to elevate their privileges locally. This article covers technical details, affected versions, impact assessment, and mitigation strategies.

CVE-2025-29976 Overview

CVE-2025-29976 is an improper privilege management vulnerability in Microsoft Office SharePoint Server. An authenticated attacker with local access to a SharePoint Server can leverage the flaw to elevate privileges on the host. The weakness is categorized under [CWE-269] Improper Privilege Management. Microsoft disclosed the issue on May 13, 2025, and no public proof-of-concept or in-the-wild exploitation has been reported. The vulnerability affects SharePoint Server Subscription Edition, SharePoint Server 2019, and SharePoint Server 2016.

Critical Impact
A successful exploit allows a low-privileged, authenticated user to gain elevated privileges on the SharePoint Server, compromising confidentiality, integrity, and availability of hosted content and configuration.

Affected Products

Microsoft SharePoint Server Subscription Edition
Microsoft SharePoint Server 2019
Microsoft SharePoint Server 2016 (Enterprise)

Discovery Timeline

2025-05-13 - CVE-2025-29976 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-29976

Vulnerability Analysis

The vulnerability resides in how Microsoft SharePoint Server manages privileges for authenticated principals operating on the server. An attacker who already holds valid credentials on the SharePoint host can perform actions that should be reserved for higher-privileged accounts. Because the attack vector is local and requires authentication, exploitation depends on the attacker having a foothold, such as a compromised service account, a low-privileged SharePoint user with server access, or a session obtained through a prior intrusion. Once escalated, the attacker can read or modify sensitive SharePoint data, alter site collection configuration, and impact service availability.

Root Cause

The issue is classified as [CWE-269] Improper Privilege Management. SharePoint fails to correctly assign, verify, or drop privileges during a specific server-side operation, allowing an authorized user to inherit or acquire rights beyond those granted by their role. Microsoft has not released detailed root-cause technical documentation beyond the security update guide.

Attack Vector

Exploitation requires local access to the SharePoint Server and valid authenticated credentials. No user interaction is required. The attacker executes the privilege escalation primitive against the SharePoint service, resulting in elevated rights within the SharePoint context on the affected host.

No verified public exploit code is available. Refer to the Microsoft Security Update Guide CVE-2025-29976 for authoritative technical details.

Detection Methods for CVE-2025-29976

Indicators of Compromise

Unexpected additions of accounts to SharePoint farm administrator groups or site collection administrator roles.
Unusual process execution under the SharePoint application pool identity or OWSTIMER.EXE context.
New or modified scheduled timer jobs, custom solutions (.wsp), or event receivers not deployed by change management.
Authenticated sessions from low-privileged accounts performing administrative operations against SharePoint web applications.

Detection Strategies

Monitor Windows Security event logs on SharePoint hosts for privilege escalation events (Event IDs 4672, 4673, 4674) associated with SharePoint service accounts.
Correlate SharePoint ULS logs with authentication logs to identify escalation from a low-privileged user to farm-level operations.
Alert on writes to HKLM\SOFTWARE\Microsoft\Shared Tools\Web Server Extensions\ and changes to the SharePoint configuration database performed by non-administrative principals.

Monitoring Recommendations

Baseline expected administrative accounts and alert on deviations in farm and site collection administrator membership.
Forward SharePoint ULS, IIS, and Windows Security logs to a centralized analytics platform for cross-correlation.
Track deployment of custom SharePoint solutions and feature activations, treating unscheduled changes as high-priority alerts.

How to Mitigate CVE-2025-29976

Immediate Actions Required

Apply the Microsoft security update for CVE-2025-29976 to all affected SharePoint Server Subscription Edition, 2019, and 2016 instances.
Audit farm administrator and site collection administrator membership and remove accounts that are not required.
Rotate credentials for SharePoint service accounts if compromise is suspected.
Restrict interactive and local logon rights on SharePoint hosts to a minimal set of administrators.

Patch Information

Microsoft has released fixes through the Security Update Guide. Administrators should install the SharePoint Server updates identified in the Microsoft Security Update Guide CVE-2025-29976. After patching, run the SharePoint Products Configuration Wizard (PSConfig) on each server in the farm to complete the update.

Workarounds

No official workaround is published by Microsoft; installing the security update is the supported remediation.
As a compensating control, enforce least privilege on SharePoint accounts and remove unnecessary local logon rights on SharePoint servers.
Segment SharePoint infrastructure from general user networks to limit which authenticated users can reach the host locally.

bash

# After installing the Microsoft update on each SharePoint server,
# run PSConfig to apply schema and configuration changes across the farm:
PSConfig.exe -cmd upgrade -inplace b2b -wait -cmd applicationcontent -install -cmd installfeatures