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
15.9%
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
1 foundWeaponization
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.
References
How this class of flaw gets exploited
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?
15.9% - meaning FIRST.org's EPSS model estimates a 15.9% probability this vulnerability will be exploited in the wild within 30 days (97% percentile among all scored CVEs).
Is there exploit tooling available for CVE-2026-58644?
Yes - a public Nuclei template referencing CVE-2026-58644 exist in public repositories we checked. We also found 1 public GitHub repositories referencing this CVE.
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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