CVE-2026-58644: Microsoft SharePoint Remote Code Execution Vulnerability

Overview

Severity

Critical (CVSS 9.8)

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C

Category

Remote Code Execution

Exploit Status

Actively Exploited

Exploitation Likelihood

Detected

Patch Tuesday

2026-Jul

Released

2026-07-14

Last Updated

2026-07-15

EPSS Score

15.87% (percentile: 96.7%)

CISA KEV

Listed — due 2026-07-19

Description

Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.

FAQ

How could an attacker exploit the vulnerability? In a network-based attack, an attacker authenticated as at least a Site Owner, could write arbitrary code to inject and execute code remotely on the SharePoint Server. I am running SharePoint Server 2016. Do the updates for SharePoint Enterprise Server 2016 also apply to the version I am running? Yes. The same KB number applies to both SharePoint Server 2016 and SharePoint Enterprise Server 2016. Customers running either version should install the security update to be protected from this vulnerability. According to the CVSS metric, the attack vector is network (AV:N) and the attack complexity is low (AC:L). What does that mean for this vulnerability? The attack vector is Network (AV:N) because this vulnerability is remotely exploitable and can be exploited from the internet. The attack complexity is Low (AC:L) because an attacker does not require significant prior knowledge of the system and can achieve repeatable success with the payload against the vulnerable component.

Known Exploits (1)

• Microsoft SharePoint Deserialization of Untrusted Data Vulnerability — added 2026-07-26T16:27:52Z

Detection & Weaponization (1 sources)

Maturity: Exploit

• Nuclei templates: Microsoft SharePoint Server - WS-Federation BinaryFormatter Deserialization RCE

Affected Products (3)

Microsoft Office

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

Security Updates (3)

• 5002880
• 5002874
• 5002873

Revision History

• 2026-07-14: Information published.
• 2026-07-14: The security update for this vulnerability was released but the CVE was inadvertently left out of the June 2026 release.
• 2026-07-15: Corrected the Exploitability Index, Exploited flag and CVSS vector which was incorrect at the time of publication on 7/14/2026. This is an informational change only.