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Out-of-bounds read in Microsoft Excel enables remote code execution

Priority MEDIUM 42CWE-125Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA.

Summary

Microsoft 365 Apps for Enterprise, Office 365 for Mac, Office LTSC 2021, Office LTSC 2024, Office LTSC for Mac 2021 and 2024, and Office Online Server are affected. An out-of-bounds read (CWE-125) lets an unauthorized attacker execute code over a network if a user interacts with crafted content.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

Description from the CNA

Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to execute code over a network.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00955 61st percentileScored 2026-11-07
Fix Fixed Microsoft 365 Apps for Enterprise (Microsoft): https://aka.ms/OfficeSecurityReleasesMicrosoft Office 365 for Mac (Microsoft): 16.114.26101123+5 more products

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
MicrosoftMicrosoft 365 Apps for Enterprise16.0.1 to before https://aka.ms/OfficeSecurityReleaseshttps://aka.ms/OfficeSecurityReleasesPatch availableCNA
MicrosoftMicrosoft Office 365 for Mac1.0.0 to before 16.114.2610112316.114.26101123Patch availableCNA
MicrosoftMicrosoft Office LTSC 202116.0.1 to before 16.0.14334.2097416.0.14334.20974Patch availableCNA
MicrosoftMicrosoft Office LTSC 202416.0.0 to before 16.0.17932.2105616.0.17932.21056Patch availableCNA
MicrosoftMicrosoft Office LTSC for Mac 202116.0.1 to before 16.114.2610112316.114.26101123Patch availableCNA
MicrosoftMicrosoft Office LTSC for Mac 202416.0.0 to before 16.114.2610112316.114.26101123Patch availableCNA
MicrosoftOffice Online Server16.0.0.0 to before 16.0.10417.2022816.0.10417.20228Patch availableCNA
  • Microsoft 365 Apps for Enterprise VendorMicrosoft Affected 16.0.1 to before https://aka.ms/OfficeSecurityReleases Fixed in https://aka.ms/OfficeSecurityReleases Patch available CNA
  • Microsoft Office 365 for Mac VendorMicrosoft Affected 1.0.0 to before 16.114.26101123 Fixed in 16.114.26101123 Patch available CNA
  • Microsoft Office LTSC 2021 VendorMicrosoft Affected 16.0.1 to before 16.0.14334.20974 Fixed in 16.0.14334.20974 Patch available CNA
  • Microsoft Office LTSC 2024 VendorMicrosoft Affected 16.0.0 to before 16.0.17932.21056 Fixed in 16.0.17932.21056 Patch available CNA
  • Microsoft Office LTSC for Mac 2021 VendorMicrosoft Affected 16.0.1 to before 16.114.26101123 Fixed in 16.114.26101123 Patch available CNA
  • Microsoft Office LTSC for Mac 2024 VendorMicrosoft Affected 16.0.0 to before 16.114.26101123 Fixed in 16.114.26101123 Patch available CNA
  • Office Online Server VendorMicrosoft Affected 16.0.0.0 to before 16.0.10417.20228 Fixed in 16.0.10417.20228 Patch available CNA

CPE configurations NVD · 10

CPEVersionsRoleVendor
cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:x64:*not specified by NVDVulnerableMicrosoft
cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:x86:*not specified by NVDVulnerableMicrosoft
cpe:2.3:a:microsoft:microsoft_365:-:*:*:*:*:macos:*:*not specified by NVDVulnerableMicrosoft
cpe:2.3:a:microsoft:office_2021:-:*:*:*:ltsc:-:x64:*not specified by NVDVulnerableMicrosoft
cpe:2.3:a:microsoft:office_2021:-:*:*:*:ltsc:-:x86:*not specified by NVDVulnerableMicrosoft
cpe:2.3:a:microsoft:office_2021:-:*:*:*:ltsc:macos:-:*not specified by NVDVulnerableMicrosoft
cpe:2.3:a:microsoft:office_2024:-:*:*:*:ltsc:-:x64:*not specified by NVDVulnerableMicrosoft
cpe:2.3:a:microsoft:office_2024:-:*:*:*:ltsc:-:x86:*not specified by NVDVulnerableMicrosoft
cpe:2.3:a:microsoft:office_2024:-:*:*:*:ltsc:macos:-:*not specified by NVDVulnerableMicrosoft
cpe:2.3:a:microsoft:office_online_server:*:*:*:*:*:*:*:*before 16.0.10417.20228VulnerableMicrosoft
  • cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:x64:* Versions not specified by NVD Vulnerable ·Microsoft
  • cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:x86:* Versions not specified by NVD Vulnerable ·Microsoft
  • cpe:2.3:a:microsoft:microsoft_365:-:*:*:*:*:macos:*:* Versions not specified by NVD Vulnerable ·Microsoft
  • cpe:2.3:a:microsoft:office_2021:-:*:*:*:ltsc:-:x64:* Versions not specified by NVD Vulnerable ·Microsoft
  • cpe:2.3:a:microsoft:office_2021:-:*:*:*:ltsc:-:x86:* Versions not specified by NVD Vulnerable ·Microsoft
  • cpe:2.3:a:microsoft:office_2021:-:*:*:*:ltsc:macos:-:* Versions not specified by NVD Vulnerable ·Microsoft
  • cpe:2.3:a:microsoft:office_2024:-:*:*:*:ltsc:-:x64:* Versions not specified by NVD Vulnerable ·Microsoft
  • cpe:2.3:a:microsoft:office_2024:-:*:*:*:ltsc:-:x86:* Versions not specified by NVD Vulnerable ·Microsoft
  • cpe:2.3:a:microsoft:office_2024:-:*:*:*:ltsc:macos:-:* Versions not specified by NVD Vulnerable ·Microsoft
  • cpe:2.3:a:microsoft:office_online_server:*:*:*:*:*:*:*:* Versions before 16.0.10417.20228 Vulnerable ·Microsoft

Remediation

Install Office 365 for Mac 16.114.26101123 or later, Office LTSC 2021 16.0.14334.20974 or later, Office LTSC 2024 16.0.17932.21056 or later, Office LTSC for Mac 2021 and 2024 16.114.26101123 or later, and Office Online Server 16.0.10417.20228 or later. Microsoft 365 Apps for Enterprise is fixed in the builds listed on the Microsoft Office security release page.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

  • Fix · CNA Microsoft 365 Apps for Enterprise (Microsoft) Fixed in https://aka.ms/OfficeSecurityReleases
  • Fix · CNA Microsoft Office 365 for Mac (Microsoft) Fixed in 16.114.26101123
  • Fix · CNA Microsoft Office LTSC 2021 (Microsoft) Fixed in 16.0.14334.20974
  • Fix · CNA Microsoft Office LTSC 2024 (Microsoft) Fixed in 16.0.17932.21056
  • Fix · CNA Microsoft Office LTSC for Mac 2021 (Microsoft) Fixed in 16.114.26101123
  • Fix · CNA Microsoft Office LTSC for Mac 2024 (Microsoft) Fixed in 16.114.26101123
  • Fix · CNA Office Online Server (Microsoft) Fixed in 16.0.10417.20228

Timeline

  1. 2026-10-13 Threatist record created from CVE-2026-105718
  2. 2026-10-13 CISA SSVC decision points changed
  3. 2026-10-13 Priority changed: MEDIUM → LOW
  4. 2026-10-13 Alias added: GHSA-v5vx-f5c6-h39j
  5. 2026-10-14 Priority changed: LOW → MEDIUM
  6. 2026-10-16 Fix available: Microsoft/Microsoft Office 365 for [email protected], Microsoft/Microsoft Office LTSC for Mac [email protected], Microsoft/Microsoft Office LTSC for Mac [email protected] · CNA

References

  • TI-2024-14173 Microsoft Outlook Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 9.8
  • TI-2023-09240 Microsoft Outlook Elevation of Privilege Vulnerability KEVCVSS 3.1CRITICAL 9.8
  • TI-2024-25471 Microsoft Project Remote Code Execution Vulnerability KEVCVSS 3.1HIGH 8.8
  • TI-2023-17652 Microsoft Outlook Security Feature Bypass Vulnerability KEVCVSS 3.1HIGH 8.8
  • TI-2026-17368 Microsoft Word Security Feature Bypass Vulnerability KEVCVSS 3.1HIGH 7.8
  • TI-2026-17363 Microsoft Office Security Feature Bypass Vulnerability KEVCVSS 3.1HIGH 7.8
See all 935 →

Sources