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Known Exploited Vulnerability
9.8
CRITICAL CVSS 3.1
CVE-2026-58644
Microsoft SharePoint Deserialization of Untrusted Data Vulnerability - [Actively Exploited]
Overview
Description

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

Details
INFO

Published Date :

July 14, 2026, 5:17 p.m.

Last Modified :

July 17, 2026, 5:16 a.m.

Remotely Exploit :

No

Source :

[email protected]
CISA Notification
CISA KEV (Known Exploited Vulnerabilities)

For the benefit of the cybersecurity community and network defenders—and to help every organization better manage vulnerabilities and keep pace with threat activity—CISA maintains the authoritative source of vulnerabilities that have been exploited in the wild.

Description :

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

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.

Known Ransomware Campaign Use:

Unknown

Notes :

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-58644 ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-58644

Impact
Affected Products

The following products are affected by CVE-2026-58644 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Microsoft sharepoint_server
2 Microsoft sharepoint_enterprise_server_2016
3 Microsoft sharepoint_server_2016
4 Microsoft sharepoint_server_2019
: Total Affected Vendor : 1 | Products : 4
Scoring
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 134c704f-9b21-4f2e-91b3-4a467353bcc0
CVSS 3.1 CRITICAL f38d906d-7342-40ea-92c1-6c4a2c6478c8
CVSS 3.1 CRITICAL [email protected]
Public PoC/Exploit Available at Github

CVE-2026-58644 has a 8 public PoC/Exploit available at Github. Go to the Public Exploits tab to see the list.

References
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-58644.

URL Resource
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-58644 Patch Vendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-58644 US Government Resource
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-58644 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-58644 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

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jamineneves54-gif/Ciberseguran-a-guia-notebooklm

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Updated: 2 weeks ago
0 stars 0 fork 0 watcher
Born at : July 20, 2026, 12:41 a.m. This repo has been linked 2 different CVEs too.
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GrijalvoMarcoLaboral/GrijalvoMarcoLaboral

None

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Updated: 2 weeks, 3 days ago
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Born at : May 27, 2026, 4:28 p.m. This repo has been linked 7 different CVEs too.
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barmi/cve-patch-auditor

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myseq/tracker

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Updated: 2 weeks, 1 day ago
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BlueShield-Ch4rl13/ScriptNewsCTI

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CryptoGenNepal/CVE-KEV-RSS

CISA maintains the authoritative source of vulnerabilities that have been exploited in the wild and CryptoGen Nepal aims to simplify this for the general public in a more understandable way as well as in a format that can be easily integrated into their threat intelligence systems.

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DevGreick/devgreick

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Updated: 2 weeks, 1 day ago
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Born at : Oct. 29, 2024, 8:10 p.m. This repo has been linked 10 different CVEs too.
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EmmanuelTsouris/ms-patch-tuesday-fetcher

None

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Updated: 2 weeks, 2 days ago
0 stars 0 fork 0 watcher
Born at : Sept. 13, 2024, 9:56 p.m. This repo has been linked 4 different CVEs too.

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-58644 vulnerability anywhere in the article.

  • security.nl
Honderden Microsoft SharePoint-servers bevatten actief misbruikte lekken

Honderden Microsoft SharePoint-servers die vanaf het internet toegankelijk zijn bevatten bekende kwetsbaarheden waar aanvallers op dit moment actief misbruik van maken. Het gaat ook om 25 SharePoint-s ... Read more

Published Date: Jul 27, 2026 (1 week ago)
  • The Hacker News
Critical SharePoint RCE CVE-2026-50522 Under Active Exploitation After Public PoC

A third SharePoint Server flaw patched by Microsoft as part of its Patch Tuesday update for July 2026 has come under active exploitation, per watchTowr. The vulnerability in question is CVE-2026-50522 ... Read more

Published Date: Jul 21, 2026 (1 week, 6 days ago)
  • security.nl
NCSC roept op tot snel installeren van updates Microsoft Office en SharePoint

Het Nationaal Cyber Security Centrum (NCSC) roept organisaties vandaag op om beveiligingsupdates voor Microsoft Office en SharePoint zo snel mogelijk te installeren. Het gaat onder andere om een patch ... Read more

Published Date: Jul 20, 2026 (2 weeks ago)
  • security.nl
Microsoft meldt alsnog actief misbruik van kritiek SharePoint-lek

Een kritieke kwetsbaarheid in Microsoft SharePoint waardoor aanvallers SharePoint-servers op afstand kunnen overnemen is toch wel actief bij aanvallen misbruikt voordat een beveiligingsupdate beschikb ... Read more

Published Date: Jul 17, 2026 (2 weeks, 3 days ago)
  • The Hacker News
CISA Adds Exploited SharePoint RCE Zero-Day CVE-2026-58644 to KEV

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) on Thursday added a newly patched security flaw impacting Microsoft SharePoint Server to its Known Exploited Vulnerabilities (KEV) cata ... Read more

Published Date: Jul 17, 2026 (2 weeks, 3 days ago)
  • Kaspersky
Key vulnerabilities of Microsoft’s July 2026 Patch Tuesday

Although experts had already warned of an impending “tsunami of vulnerabilities” back in April, immediately following the announcement of the Mythos AI model, concrete evidence began to emerge over th ... Read more

Published Date: Jul 15, 2026 (2 weeks, 5 days ago)
  • security.nl
Microsoft SharePoint-servers aangevallen, VS roept op tot extra beveiliging

Aanvallers maken actief misbruik van verschillende kwetsbaarheden voor het aanvallen van Microsoft SharePoint-servers, zo waarschuwt het Amerikaanse cyberagentschap CISA. Dat roept organisaties op om ... Read more

Published Date: Jul 15, 2026 (2 weeks, 5 days ago)
  • CrowdStrike.com
July 2026 Patch Tuesday: Microsoft Patches 622 Vulnerabilities Including Two Exploited Zero-Days

Microsoft has addressed 622 vulnerabilities in its July 2026 security update release. Based on CrowdStrike’s analysis, this represents roughly triple the number of vulnerabilities in June, and almost ... Read more

Published Date: Jul 15, 2026 (2 weeks, 5 days ago)

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-58644 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Jul. 17, 2026

    Action Type Old Value New Value
    Changed SSVC {'id': 'CVE-2026-58644', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'active'}, {'automatable': 'yes'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-07-16T17:45:03.866495Z'} {'id': 'CVE-2026-58644', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'active'}, {'automatable': 'yes'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-07-16T00:00:00+00:00'}
  • Modified Analysis by [email protected]

    Jul. 16, 2026

    Action Type Old Value New Value
    Added Reference Type CISA-ADP: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-58644 Types: US Government Resource
  • CVE CISA KEV Update by 9119a7d8-5eab-497f-8521-727c672e3725

    Jul. 16, 2026

    Action Type Old Value New Value
    Added Date Added 2026-07-16
    Added Due Date 2026-07-16
    Added Required Action 2026-07-16
    Added Vulnerability Name 2026-07-16
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Jul. 16, 2026

    Action Type Old Value New Value
    Added Reference https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-58644
    Changed SSVC {'id': 'CVE-2026-58644', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'yes'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-07-16T15:14:24.171527Z'} {'id': 'CVE-2026-58644', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'active'}, {'automatable': 'yes'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-07-16T17:45:03.866495Z'}
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Jul. 16, 2026

    Action Type Old Value New Value
    Added SSVC {'id': 'CVE-2026-58644', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'yes'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-07-16T15:14:24.171527Z'}
  • Initial Analysis by [email protected]

    Jul. 15, 2026

    Action Type Old Value New Value
    Added CPE Configuration OR *cpe:2.3:a:microsoft:sharepoint_server:2019:*:*:*:*:*:*:* *cpe:2.3:a:microsoft:sharepoint_server:2016:*:*:*:enterprise:*:*:* *cpe:2.3:a:microsoft:sharepoint_server:*:*:*:*:subscription:*:*:* versions up to (excluding) 16.0.19725.20434
    Added Reference Type Microsoft Corporation: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-58644 Types: Patch, Vendor Advisory
  • New CVE Received by [email protected]

    Jul. 14, 2026

    Action Type Old Value New Value
    Added Affected [{'vendor': 'Microsoft', 'product': 'Microsoft SharePoint Enterprise Server 2016', 'versions': [{'status': 'affected', 'version': '16.0.0', 'lessThan': '16.0.5556.1005', 'versionType': 'custom'}], 'platforms': ['x64-based Systems']}, {'vendor': 'Microsoft', 'product': 'Microsoft SharePoint Server 2019', 'versions': [{'status': 'affected', 'version': '16.0.0', 'lessThan': '16.0.10417.20153', 'versionType': 'custom'}], 'platforms': ['x64-based Systems']}, {'vendor': 'Microsoft', 'product': 'Microsoft SharePoint Server Subscription Edition', 'versions': [{'status': 'affected', 'version': '16.0.0', 'lessThan': '16.0.19725.20384', 'versionType': 'custom'}], 'platforms': ['x64-based Systems']}]
    Added Description Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    Added CWE CWE-502
    Added Reference https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-58644
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CVSS
Vulnerability Scoring Details
Base CVSS Score: 9.8
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact