Microsoft SharePoint Code Injection (CVE-2025-49704) and Patch Bypass

Historical catalog analysis: CISA added this entry on July 22, 2025. The entry reflects catalog information retrieved on August 31, 2026, not a snapshot archived on the inclusion date. Check current vendor guidance before acting.

What the vulnerability is

CVE-2025-49704 is a code injection vulnerability (CWE-94) affecting Microsoft SharePoint. The flaw allows an authorized attacker to execute code over a network. This vulnerability can be chained with CVE-2025-49706 to increase impact. Furthermore, CVE-2025-53770 has been identified as a patch bypass for CVE-2025-49704; updates addressing the bypass provide more robust protection than those targeting the initial vulnerability alone.

Exposure and applicability

This vulnerability applies to Microsoft SharePoint installations. The risk is highest for organizations running public-facing instances of the software. Specifically, versions that have reached end-of-life (EOL) or end-of-service (EOS), including SharePoint Server 2013 and earlier, are identified as critical exposure points because they lack vendor support for modern mitigations.

Potential breach-prevention strategy

The source reports that this vulnerability is known to be used in ransomware campaigns. The reported entry path involves an authorized attacker executing code over the network, though the specific method of authorization or initial access remains unknown.

Our analysis suggests a similar breach could have been mitigated through the following prioritized actions:

1. Decommission EOL/EOS Assets: Public-facing SharePoint Server 2013 and earlier versions should be disconnected. This addresses the scenario where legacy systems cannot be patched against known ransomware vectors. Responsible Role: Infrastructure Owner. Verification: Network scan confirming the asset is no longer reachable via public interfaces.
2. Prioritize Bypass Remediation: Deploy updates for CVE-2025-53770 rather than relying solely on the initial fix for CVE-2025-49704. This addresses the hypothetical scenario where an attacker uses a patch bypass to circumvent early remediation efforts. Responsible Role: Vulnerability Management Team. Verification: Confirmation of the specific update version that addresses the bypass.
3. Restrict Network Exposure: Limit network access to SharePoint management interfaces to authorized administrative segments only. This is intended to limit damage by reducing the number of potential paths an authorized attacker can use to execute code over the network. Responsible Role: Network Security Engineer. Verification: Firewall rule audit and connectivity tests from unauthorized zones.

Remediation priorities

Remediation should be prioritized based on asset lifecycle and exposure:
* Immediate Action (Legacy): Disconnect all public-facing SharePoint Server 2013 and earlier versions, as these are EOL/EOS.
* High Priority (Supported): For supported versions, apply vendor updates. Priority must be given to the updates for CVE-2025-53770 due to its status as a patch bypass for CVE-2025-49704.
* Secondary Action: Review and implement CISA and vendor mitigation instructions for all remaining supported instances.

How to validate remediation

Verification must move beyond simple version checks. To prove exposure was reduced, defenders should:
1. Verify Asset Status: Confirm that EOL/EOS servers are physically or logically disconnected from public-facing networks.
2. Validate Patch Depth: Ensure the installed update specifically addresses CVE-2025-53770 to confirm the bypass is mitigated, not just the original vulnerability.
3. Confirm Access Controls: Use authorized network testing to verify that only required, authorized users can reach the SharePoint service over the network.

Limits and open questions

Applying a patch for CVE-2025-49704 without addressing CVE-2025-53770 leaves a residual risk of exploitation via the bypass. Additionally, while disconnecting public-facing EOL systems reduces external exposure, internal risks remain if these legacy systems are still accessible to authorized users within the network. It remains unknown exactly how attackers are obtaining the authorization required to trigger the code injection.

Source and editorial note

CVE-2025-49704: Microsoft SharePoint Code Injection Vulnerability · Source date: July 22, 2025 · Retrieved August 31, 2026.

Material facts are tied to the cited primary source. Recommendations are independent defensive analysis unless attributed to the source. Confirm consequential decisions against current authoritative guidance.

Archive date: July 25, 2025. The displayed post date is assigned three days after the source date to organize this retrospective archive; it does not mean this site published the analysis then. First published by this site: October 08, 2026 at 00:15 UTC.

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