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CVE-2026-58644

Microsoft SharePoint Deserialization of Untrusted Data

9.8 CRITICALActively exploited (CISA KEV)EPSS 15.9%
  1. Published14 Jul 2026
  2. Added to CISA KEV16 Jul 2026
  3. Remediation due19 Jul 2026
Actively exploited (CISA KEV)

Microsoft SharePoint contains a deserialization of untrusted data vulnerability that allows an unauthorized attacker to execute code over a network.

Added to KEV: 16 Jul 2026Federal remediation due: 19 Jul 2026

Description

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

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Microsoft SharePoint Server2016 · 2019 · < 16.0.19725.20434

Remediation

Fixed in
Microsoft SharePoint Server≥ 16.0.19725.20434

References

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Frequently asked

Is CVE-2026-58644 being actively exploited?

Yes. CVE-2026-58644 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 16 Jul 2026.

How severe is CVE-2026-58644?

CVE-2026-58644 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 15.9% probability of exploitation.

Which products are affected by CVE-2026-58644?

Affected products include Microsoft SharePoint Server.

How do I fix CVE-2026-58644?

Upgrade affected software to a fixed version, for example Microsoft SharePoint Server 16.0.19725.20434 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-58644 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, a risk for it never ranks below high, and the update that fixes it moves to the Emergency patch lane. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.