Deserialization in Microsoft Sharepoint Enterprise Server 2016
CVE-2026-58644
Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.
Vulnerability class: Insecure Deserialization
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.159 (96.8th percentile), scored .
Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 97th percentile — 96.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.159 · newest: 0.159 · change: 0.000
Affected products
- Microsoft Sharepoint Enterprise Server 2016 — versions 16.0.0
- Microsoft Sharepoint Server 2019 — versions 16.0.0
- Microsoft Sharepoint Server Subscription Edition — versions 16.0.0
- Microsoft Sharepoint Server — versions 2016, 2019
Weakness classification (CWE)
CISA KEV (Known Exploited Vulnerabilities)
This CVE is on the CISA KEV catalog, added on . CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.
BOD 22-01 due date: .
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.
References
- Microsoft SharePoint Remote Code Execution Vulnerability (vendor-advisory, Patch, patch, Vendor Advisory)
- 134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)
Frequently asked questions
- What is CVE-2026-58644?
- CVE-2026-58644 is a critical-severity vulnerability in Microsoft Sharepoint Enterprise Server 2016, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2026-07-14.
- How severe is CVE-2026-58644?
- Critical severity. CVSS v3 base score is 9.8 out of 10.
- Is CVE-2026-58644 known to be exploited?
- Yes. CVE-2026-58644 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-07-16), indicating it is being actively exploited.