Vulnerability-Lookup

MSRC_CVE-2026-40420

Vulnerability from csaf_microsoft - Published: 2026-05-12 07:00 - Updated: 2026-05-12 07:00

Summary

Microsoft Office Click-To-Run Elevation of Privilege Vulnerability

Severity

Important

Notes

Additional Resources: To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle

Disclaimer: The information provided in the Microsoft Knowledge Base is provided \"as is\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

Customer Action: Required. The vulnerability documented by this CVE requires customer action to resolve.

CVE-2026-40420

8.8 (High)


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

CWE-284 - Improper Access Control

Affected products

Fixed 8 products

Product	Identifier	Version	Remediation
Microsoft Office 2019 for 32-bit editions https://aka.ms/OfficeSecurityReleases Microsoft Office 2019 for 32-bit editions		https://aka.ms/OfficeSecurityReleases
Microsoft Office 2019 for 64-bit editions https://aka.ms/OfficeSecurityReleases Microsoft Office 2019 for 64-bit editions		https://aka.ms/OfficeSecurityReleases
Microsoft 365 Apps for Enterprise for 32-bit Systems https://aka.ms/OfficeSecurityReleases Microsoft 365 Apps for Enterprise for 32-bit Systems		https://aka.ms/OfficeSecurityReleases
Microsoft 365 Apps for Enterprise for 64-bit Systems https://aka.ms/OfficeSecurityReleases Microsoft 365 Apps for Enterprise for 64-bit Systems		https://aka.ms/OfficeSecurityReleases
Microsoft Office LTSC 2021 for 64-bit editions https://aka.ms/OfficeSecurityReleases Microsoft Office LTSC 2021 for 64-bit editions		https://aka.ms/OfficeSecurityReleases
Microsoft Office LTSC 2021 for 32-bit editions https://aka.ms/OfficeSecurityReleases Microsoft Office LTSC 2021 for 32-bit editions		https://aka.ms/OfficeSecurityReleases
Microsoft Office LTSC 2024 for 32-bit editions https://aka.ms/OfficeSecurityReleases Microsoft Office LTSC 2024 for 32-bit editions		https://aka.ms/OfficeSecurityReleases
Microsoft Office LTSC 2024 for 64-bit editions https://aka.ms/OfficeSecurityReleases Microsoft Office LTSC 2024 for 64-bit editions		https://aka.ms/OfficeSecurityReleases

Known affected 8 products

Product	Version	Remediation
Microsoft Office LTSC 2024 for 64-bit editions <https://aka.ms/OfficeSecurityReleases Microsoft Office LTSC 2024 for 64-bit editions	<https://aka.ms/OfficeSecurityReleases	Vendor Fix fix
Microsoft Office LTSC 2024 for 32-bit editions <https://aka.ms/OfficeSecurityReleases Microsoft Office LTSC 2024 for 32-bit editions	<https://aka.ms/OfficeSecurityReleases	Vendor Fix fix
Microsoft Office LTSC 2021 for 32-bit editions <https://aka.ms/OfficeSecurityReleases Microsoft Office LTSC 2021 for 32-bit editions	<https://aka.ms/OfficeSecurityReleases	Vendor Fix fix
Microsoft Office LTSC 2021 for 64-bit editions <https://aka.ms/OfficeSecurityReleases Microsoft Office LTSC 2021 for 64-bit editions	<https://aka.ms/OfficeSecurityReleases	Vendor Fix fix
Microsoft 365 Apps for Enterprise for 64-bit Systems <https://aka.ms/OfficeSecurityReleases Microsoft 365 Apps for Enterprise for 64-bit Systems	<https://aka.ms/OfficeSecurityReleases	Vendor Fix fix
Microsoft 365 Apps for Enterprise for 32-bit Systems <https://aka.ms/OfficeSecurityReleases Microsoft 365 Apps for Enterprise for 32-bit Systems	<https://aka.ms/OfficeSecurityReleases	Vendor Fix fix
Microsoft Office 2019 for 64-bit editions <https://aka.ms/OfficeSecurityReleases Microsoft Office 2019 for 64-bit editions	<https://aka.ms/OfficeSecurityReleases	Vendor Fix fix
Microsoft Office 2019 for 32-bit editions <https://aka.ms/OfficeSecurityReleases Microsoft Office 2019 for 32-bit editions	<https://aka.ms/OfficeSecurityReleases	Vendor Fix fix

Threats

Impact Elevation of Privilege

Exploit Status Publicly Disclosed:No;Exploited:No;Latest Software Release:Exploitation Less Likely

References

7 references

URL	Category
https://msrc.microsoft.com/update-guide/vulnerabi…	self
https://msrc.microsoft.com/csaf/advisories/2026/m…	self
https://www.microsoft.com/en-us/msrc/exploitabili…	external
https://support.microsoft.com/lifecycle	external
https://www.first.org/cvss	external
https://msrc.microsoft.com/update-guide/vulnerabi…	self
https://msrc.microsoft.com/csaf/advisories/2026/m…	self

Acknowledgments

Ben Lichtman with Microsoft

JSON

To clipboard

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}

CVE-2026-40420 (GCVE-0-2026-40420)

Vulnerability from cvelistv5 – Published: 2026-05-12 16:59 – Updated: 2026-05-14 18:08

Title

Microsoft Office Click-To-Run Elevation of Privilege Vulnerability

Summary

Improper access control in Microsoft Office Click-To-Run allows an authorized attacker to elevate privileges locally.

Severity ?

8.8 (High)


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

CWE

CWE-284 - Improper Access Control

Assigner

microsoft

References

1 reference

URL	Tags
https://msrc.microsoft.com/update-guide/vulnerabi…	vendor-advisorypatch

Impacted products

4 products

Vendor	Product	Version
Microsoft	Microsoft 365 Apps for Enterprise	Affected: 16.0.1 , < https://aka.ms/OfficeSecurityReleases (custom)
Microsoft	Microsoft Office 2019	Affected: 19.0.0 , < https://aka.ms/OfficeSecurityReleases (custom)
Microsoft	Microsoft Office LTSC 2021	Affected: 16.0.1 , < https://aka.ms/OfficeSecurityReleases (custom)
Microsoft	Microsoft Office LTSC 2024	Affected: 16.0.0 , < https://aka.ms/OfficeSecurityReleases (custom)

Date Public ?

2026-05-12 14:00

Show details on NVD website

JSON

To clipboard

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    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

MSRC_CVE-2026-40420

CVE-2026-40420 (GCVE-0-2026-40420)

Tags

Sightings

Nomenclature