Microsoft SharePoint Deserialization of Untrusted Data Vulnerability
Microsoft — Microsoft SharePoint Enterprise Server 2016
Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.
9.8
1.5%
Vector breakdown
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Published
- Jul 14, 2026
- Modified
- Jul 17, 2026
- Added to KEV
- Jul 16, 2026
- Federal patch due
- Jul 19, 2026
CISA 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.
Weakness classification
Affected packages
Proof-of-concept & exploitation references
Weaponization
Public repositories whose name or description references CVE-2026-58644, found via a live GitHub search at request time. These are community-sourced signals, not a verified working exploit - cross-check each one before relying on it, and treat higher star counts and recent activity as (weak) corroboration, not proof.
No public GitHub repositories referencing CVE-2026-58644 were found at last check. Absence here is not proof no exploit exists - see the references below for vendor advisories and write-ups.
References
Frequently asked questions
What is CVE-2026-58644?
Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.
How severe is CVE-2026-58644?
CVE-2026-58644 has a CVSS base score of 9.8 out of 10 (CVSS 3.1).
Is CVE-2026-58644 actively exploited in the wild?
Yes. CVE-2026-58644 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added Jul 16, 2026, meaning CISA has confirmed evidence of active exploitation.
What is the EPSS score for CVE-2026-58644?
1.5% - meaning FIRST.org's EPSS model estimates a 1.5% probability this vulnerability will be exploited in the wild within 30 days (71% percentile among all scored CVEs).
What type of vulnerability is CVE-2026-58644?
CVE-2026-58644 is classified under CWE-502 (CWE-502: Deserialization of Untrusted Data).
Cross-checked against
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