Which products and versions are affected by CVE-2026-58644?

Affected: Sharepoint Server (Microsoft) versions 2016, 2019; Sharepoint Server 2016 (Microsoft); Sharepoint Server 2019 (Microsoft) versions >= 16.0.0, among others. The full list is in the CVE brief.

Is CVE-2026-58644 being exploited in the wild?

It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Jul 14, 2026.

Is CVE-2026-58644 in the CISA KEV catalog?

Yes. It was added on Jul 16, 2026 with a federal remediation due date of Jul 19, 2026.

Is there a public exploit for CVE-2026-58644?

Public exploit code is available.

How urgently should CVE-2026-58644 be patched?

Brandefense priority: patch immediately, because it is listed as exploited in the wild.

Request A Demo

Vulnerability Intelligence

CVE-2026-58644

CriticalExploitedPublic exploit

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

Published Jul 14, 2026 · Updated Oct 8, 2026

Key Facts

Patch immediately

CVE-2026-58644 is a critical-severity vulnerability (CVSS 9.8 v3.1) affecting Sharepoint Server (Microsoft), Sharepoint Server 2016 (Microsoft), Sharepoint Server 2019 (Microsoft) and 2 more products.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Jul 14, 2026. Public exploit code is available.
EPSS estimates a 16% probability of exploitation in the next 30 days.
Fixed versions are available, including Microsoft SharePoint Enterprise Server 2016 16.0.5556.1005, Sharepoint Server 16.0.19725.20384, Sharepoint Server 16.0.19725.20434.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.

CVSS v3.1

9.8

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C

EPSS (30-day exploit likelihood)

16%

Higher than 96.8% of all scored CVEs

Exploited in the wild

Yes

4 catalog listings

Public exploit code

Available

Proof-of-concept or weaponized module

Get the full CVE-2026-58644 brief as a PDF

Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.

Description

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

Known-Exploited Catalog Listings

Catalog	Added	Remediation due	Ransomware use
CISA KEV	Jul 16, 2026	Jul 19, 2026	Not reported
Industry KEV feed	Jul 14, 2026	Jul 19, 2026	Not reported
CIRCL KEV	Jul 14, 2026	Jul 19, 2026	Not reported
ENISA EUVD	Jul 16, 2026	n/a	Not reported

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.

Affected Products

9 affected entries in total

Product	Affected versions	Fixed in
Sharepoint ServerMicrosoft	2016, 2019	16.0.19725.20434
Sharepoint Server 2016Microsoft	See advisory	16.0.5556.1005
Sharepoint Server 2019Microsoft	>= 16.0.0	16.0.10417.20153
Microsoft SharePoint Enterprise Server 2016	>= 16.0.0	16.0.5556.1005
Microsoft SharePoint Server Subscription Edition	>= 16.0.0	16.0.19725.20384

Patched Releases

Microsoft SharePoint Enterprise Server 2016

16.0.5556.1005

Sharepoint Server

16.0.19725.20384, 16.0.19725.20434

Sharepoint Server 2019

16.0.10417.20153

Microsoft SharePoint Server Subscription Edition

16.0.19725.20384

Timeline

Publicly disclosed
Jul 14, 2026
Added to Industry KEV feed
Jul 14, 2026
Added to CIRCL KEV
Jul 14, 2026
Added to CISA KEV
Jul 16, 2026
Added to ENISA EUVD
Jul 16, 2026
Last updated
Oct 8, 2026

Weakness Type

CWE-502 Deserialization of Untrusted Data

References

3 more references in the full CVE brief

FAQ

Common Questions.

Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.
Affected: Sharepoint Server (Microsoft) versions 2016, 2019; Sharepoint Server 2016 (Microsoft); Sharepoint Server 2019 (Microsoft) versions >= 16.0.0, among others. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Jul 14, 2026.
Yes. It was added on Jul 16, 2026 with a federal remediation due date of Jul 19, 2026.
Public exploit code is available.
Fixed versions are available, including Microsoft SharePoint Enterprise Server 2016 16.0.5556.1005, Sharepoint Server 16.0.19725.20384, Sharepoint Server 16.0.19725.20434.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.

Is CVE-2026-58644 Running On Your Attack Surface?

Brandefense maps vulnerabilities like this one to your internet-facing assets and tells you exactly where to patch.