CVE-2025-53760: Microsoft SharePoint Server SSRF Vulnerability

CVE-2025-53760 Overview

CVE-2025-53760 is a Server-Side Request Forgery (SSRF) vulnerability in Microsoft Office SharePoint that allows an authenticated attacker to elevate privileges over a network. The flaw is tracked under CWE-918 and affects SharePoint Server Subscription Edition, SharePoint Server 2019, and SharePoint Server 2016. An authorized attacker with low privileges can coerce the SharePoint server into issuing crafted requests to internal or external endpoints, leveraging the server's identity to access resources the attacker cannot reach directly.

Critical Impact

Authenticated attackers can abuse SharePoint to issue server-side requests, exposing internal services and enabling privilege escalation across the network.

Affected Products

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

Discovery Timeline

• 2025-08-12 - CVE-2025-53760 published to NVD
• 2025-08-15 - Last updated in NVD database

Technical Details for CVE-2025-53760

Vulnerability Analysis

The vulnerability resides in SharePoint Server's handling of user-supplied URLs or resource identifiers that the server fetches on behalf of the requester. Insufficient validation of these destinations allows an authenticated attacker to direct the server to arbitrary endpoints. Because SharePoint executes these requests using its own service context, the attacker can reach internal services, metadata endpoints, or trusted systems that are otherwise blocked by network controls.

Successful exploitation yields a high impact to confidentiality and a limited impact to integrity, with no direct impact to availability. The attack vector is network-based, complexity is low, and exploitation requires low privileges with no user interaction. Microsoft classifies the outcome as elevation of privilege, reflecting the attacker's ability to act through SharePoint to access privileged resources.

Root Cause

The root cause is improper validation of server-side request destinations, consistent with CWE-918: Server-Side Request Forgery. SharePoint accepts attacker-controlled input that influences the target of an outbound HTTP request without sufficient allowlisting, scheme restriction, or destination filtering.

Attack Vector

An attacker authenticates to a SharePoint site with low-privileged credentials and submits a request containing a crafted URL that the server dereferences. The server-initiated request inherits SharePoint's network position and service identity. This enables enumeration of internal hosts, retrieval of metadata from cloud or management endpoints, and interaction with services that implicitly trust intra-host or intra-network callers. See the Microsoft CVE-2025-53760 Advisory for vendor-specific exploitation context.

Detection Methods for CVE-2025-53760

Indicators of Compromise

• Outbound HTTP requests originating from SharePoint server processes (w3wp.exe) to internal IP ranges, loopback addresses, or cloud metadata endpoints such as 169.254.169.254.
• Unusual SharePoint IIS log entries containing URL parameters with embedded schemes (http://, https://, file://, gopher://) targeting non-SharePoint hosts.
• Authenticated low-privilege accounts issuing repeated requests to SharePoint endpoints known to fetch remote resources.

Detection Strategies

• Inspect IIS and SharePoint ULS logs for anomalous request parameters that contain URL-encoded internal hostnames or IP literals.
• Correlate authenticated SharePoint sessions with subsequent outbound connections from the SharePoint application pool to non-standard destinations.
• Apply CWE-918 detection signatures in web application firewalls and SIEM rules targeting SSRF patterns against SharePoint endpoints.

Monitoring Recommendations

• Baseline expected outbound network destinations for SharePoint servers and alert on deviations, particularly traffic to private ranges and metadata services.
• Monitor authentication events for low-privilege accounts that begin interacting with SharePoint resource-fetching APIs.
• Forward SharePoint, IIS, and network flow logs to a centralized analytics platform such as Singularity Data Lake for cross-source correlation and retention.

How to Mitigate CVE-2025-53760

Immediate Actions Required

• Apply the Microsoft security updates referenced in the Microsoft CVE-2025-53760 Advisory to all affected SharePoint Server instances.
• Inventory SharePoint Server Subscription Edition, 2019, and 2016 deployments and prioritize internet-exposed or multi-tenant farms.
• Review SharePoint authentication logs for suspicious low-privilege account activity preceding the patch window.

Patch Information

Microsoft has issued security updates for SharePoint Server Subscription Edition, SharePoint Server 2019, and SharePoint Server 2016. Administrators should consult the Microsoft CVE-2025-53760 Advisory for the specific KB articles and build numbers applicable to each supported version, then deploy through standard SharePoint patching procedures including farm configuration wizard execution where required.

Workarounds

• Restrict SharePoint server egress traffic with firewall rules that deny access to internal management networks, cloud metadata endpoints, and unused external destinations.
• Enforce least privilege on SharePoint user accounts and disable anonymous or guest access where business requirements permit.
• Place a web application firewall in front of SharePoint to block requests containing suspicious URL parameters indicative of SSRF payloads.

# Example: restrict SharePoint server egress to cloud metadata endpoint (Windows Firewall)
New-NetFirewallRule -DisplayName "Block-Metadata-169.254.169.254" `
  -Direction Outbound `
  -RemoteAddress 169.254.169.254 `
  -Action Block `
  -Profile Any