CVE-2026-58644
9.8, critical Known exploitedMicrosoft SharePoint Deserialization of Untrusted Data Vulnerability
- CVSS
- 9.8, critical critical CVSS v3.1
- EPSS, next 30 days
- 16% higher than 96.8% of scored CVEs
- Exploitation
- Confirmed in the wild
- Published
- 14 Jul 20263 months ago
Known exploited
CISA added this to the Known Exploited Vulnerabilities Catalog on 16 Jul 2026. US federal agencies had to remediate by 19 Jul 2026, a deadline that has passed.
Required action. Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
Description
Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.
Details
- Vendor
- Microsoft
- Product
- Microsoft SharePoint Enterprise Server 2016
- Weakness
- CWE-502 (opens in a new tab)
- Status
- Analyzed
- Updated
- 17 Jul 2026
- Assigner
- secure@microsoft.com
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References 2
Patches and fixes 1
The kind is read from NVD's tags where present and from the shape of the URL otherwise, so treat it as a hint.
Other Microsoft CVEs
Every Microsoft CVE we holdSame vendor in what we hold, not a known link between the flaws.
- CVE-2026-96951 Microsoft Windows Command Injection Vulnerability KEV EPSS 2% 8.8, high
- CVE-2026-81963 Microsoft Windows Link Following Vulnerability KEV EPSS 0.4% 7.8, high
- CVE-2026-85880 Microsoft Windows Heap-Based Buffer Overflow Vulnerability KEV EPSS 4% 7.8, high
- CVE-2026-65660 Microsoft SharePoint Code Injection Vulnerability KEV EPSS 2% 8.8, high
- CVE-2026-68820 Microsoft Windows Ancillary Function Driver for WinSock Use-After-Free Vulnerability KEV EPSS 0.3% 7, high
- CVE-2026-50522 Microsoft SharePoint Deserialization of Untrusted Data Vulnerability KEV EPSS 3% 9.8, critical
- CVE-2026-56155 Microsoft Active Directory Federation Services Insufficient Granularity of Access Control Vulnerability KEV EPSS 0.3% 7.8, high
- CVE-2026-56164 Microsoft SharePoint Server Missing Authentication for Critical Function Vulnerability KEV EPSS 1% 9.8, critical
Beyond this page
Is CVE-2026-58644 in your network?
This page tells you how dangerous CVE-2026-58644 is out there. Whether it sits on one of your devices, only a scan of your own network can tell. That is what our systems do, every day, for the companies we protect.
CVE-2026-58644 is in the CISA catalogue of exploited vulnerabilities: attackers are already exploiting it.
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EXYS7600 OCELOT
Find it before attackers do
Ocelot scans your network on a schedule and reports every vulnerability it finds by its CVE identifier, with its CVSS score and how many of your hosts are affected. A finding like CVE-2026-58644 comes with the devices to patch.
Learn more about EXYS7600 OCELOT -
EXYS7950 KONDRA
Detect it if it's exploited
Until the patch is applied, Kondra monitors your network, events and endpoints in real time. It keeps an inventory of the software installed on every endpoint, and its anomaly detection rules flag what an attacker does once inside.
Learn more about EXYS7950 KONDRA
Assembled from the NVD 2.0 API, the CISA Known Exploited Vulnerabilities Catalog and FIRST EPSS. Scores are as of our last collection on 17 Oct 2026, not the live upstream state.