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CVE-2026-40367· NVD / CVE Program· CNA microsoft

Microsoft Word Remote Code Execution Vulnerability

Access of resource using incompatible type ('type confusion') in Microsoft Office Word allows an unauthorized attacker to execute code locally.

HighCVSS 8.4 · v3.1—No exploit No fix recorded
Published
May 12, 2026
Updated
Aug 10, 2026
EPSS
0.4% · 36th percentile
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Action score

33

Monitor

Low priority for now.

CVSS
33 / 40 · 8.4 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · microsoft
8.4
NVD has not scored this yet; the score shown is the CNA’s.

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Affected systems

VendorProduct
microsoft365 apps
microsoftoffice
microsoftoffice long term servicing channel
microsoftsharepoint server
microsoftword

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • microsoft 365 appsall versions
  • microsoft office2019
  • microsoft office long term servicing channel2021
  • microsoft office long term servicing channel2024
  • microsoft sharepoint serverbefore 16.0.19725.20280
  • microsoft sharepoint server2016
  • microsoft sharepoint server2019
  • microsoft word2016

Versions reported by the vendor

Affected version ranges reported by the assigning authority (microsoft). Independent of NVD's CPE analysis and usually ahead of it.

  • Microsoft Microsoft 365 Apps for Enterprise

    • 16.0.1 and later · before https://aka.ms/OfficeSecurityReleasesaffected
  • Microsoft Microsoft Office 2019

    • 19.0.0 and later · before https://aka.ms/OfficeSecurityReleasesaffected
  • Microsoft Microsoft Office LTSC 2021

    • 16.0.1 and later · before https://aka.ms/OfficeSecurityReleasesaffected
  • Microsoft Microsoft Office LTSC 2024

    • 16.0.0 and later · before https://aka.ms/OfficeSecurityReleasesaffected
  • Microsoft Microsoft Office LTSC for Mac 2021

    • 16.0.1 and later · before 16.109.26051019affected
  • Microsoft Microsoft Office LTSC for Mac 2024

    • 16.0.0 and later · before 16.109.26051019affected
  • Microsoft Microsoft SharePoint Enterprise Server 2016

    • 16.0.0 and later · before 16.0.5552.1002affected
  • Microsoft Microsoft SharePoint Server 2019

    • 16.0.0 and later · before 16.0.10417.20128affected
  • Microsoft Microsoft SharePoint Server Subscription Edition

    • 16.0.0 and later · before 16.0.19725.20280affected
  • Microsoft Microsoft Word 2016

    • 16.0.1 and later · before 16.0.5552.1000affected

Other highest-scoring records for the same primary product.

  • CVE-2023-23397Microsoft Outlook Elevation of Privilege VulnerabilityKEV
    98Now
  • CVE-2024-21413Microsoft Outlook Remote Code Execution VulnerabilityKEV
    97Now
  • CVE-2026-21509Microsoft Office Security Feature Bypass VulnerabilityKEV
    82Now
  • CVE-2021-42292Microsoft Excel Security Feature Bypass VulnerabilityKEV
    74This week
  • CVE-2023-35311Microsoft Outlook Security Feature Bypass VulnerabilityKEV
    70This week
  • CVE-2024-38189Microsoft Project Remote Code Execution VulnerabilityKEV
    67This week

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-3311428 days apartMicrosoft Word Remote Code Execution Vulnerability
    33Monitor
  • CVE-2026-4547128 days apartMicrosoft Word Remote Code Execution Vulnerability
    31Monitor
  • CVE-2026-4564328 days apartMicrosoft Word Remote Code Execution Vulnerability
    31Monitor
  • CVE-2026-4564528 days apartMicrosoft Office Remote Code Execution Vulnerability
    31Monitor
  • CVE-2026-2611263 days apartMicrosoft Excel Remote Code Execution Vulnerability
    31Monitor
  • CVE-2026-5513663 days apartMicrosoft Excel Remote Code Execution Vulnerability
    31Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

We use this product, ask for help

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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