Heap-based buffer overflow in Microsoft Office Excel allows code execution
Priority MEDIUM 42CWE-122Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Microsoft. Impact type from Microsoft.
Summary
Microsoft Office Excel, including Microsoft 365 Apps for Enterprise, Office LTSC 2021, Office LTSC 2024, Office 365 for Mac and other products, contains a heap-based buffer overflow (CWE-122). An unauthorized remote attacker can execute code over a network when a user interacts with the product. The sources do not report known exploitation or public disclosure.
Written with Claude Haiku 5.5 from the sources below · 2026-10-28
Description from the CNA
Heap-based buffer overflow 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 0.00841 58th percentileScored 2026-11-07
Fix Fixed Microsoft: 1 update
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
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Microsoft | Microsoft 365 Apps for Enterprise | 16.0.1 to before https://aka.ms/OfficeSecurityReleases | https://aka.ms/OfficeSecurityReleases | Patch available | CNA |
| Microsoft | Microsoft Office 365 for Mac | 1.0.0 to before 16.114.26101123 | 16.114.26101123 | Patch available | CNA |
| Microsoft | Microsoft Office LTSC 2021 | 16.0.1 to before 16.0.14334.20974 | 16.0.14334.20974 | Patch available | CNA |
| Microsoft | Microsoft Office LTSC 2024 | 16.0.0 to before 16.0.17932.21056 | 16.0.17932.21056 | Patch available | CNA |
| Microsoft | Microsoft Office LTSC for Mac 2021 | 16.0.1 to before 16.114.26101123 | 16.114.26101123 | Patch available | CNA |
| Microsoft | Microsoft Office LTSC for Mac 2024 | 16.0.0 to before 16.114.26101123 | 16.114.26101123 | Patch available | CNA |
| Microsoft | Office Online Server | 16.0.0.0 to before 16.0.10417.20228 | 16.0.10417.20228 | Patch available | CNA |
- 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
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:x64:* | not specified by NVD | Vulnerable | Microsoft |
| cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:x86:* | not specified by NVD | Vulnerable | Microsoft |
| cpe:2.3:a:microsoft:microsoft_365:-:*:*:*:*:macos:*:* | not specified by NVD | Vulnerable | Microsoft |
| cpe:2.3:a:microsoft:office_2021:-:*:*:*:ltsc:-:x64:* | not specified by NVD | Vulnerable | Microsoft |
| cpe:2.3:a:microsoft:office_2021:-:*:*:*:ltsc:-:x86:* | not specified by NVD | Vulnerable | Microsoft |
| cpe:2.3:a:microsoft:office_2021:-:*:*:*:ltsc:macos:-:* | not specified by NVD | Vulnerable | Microsoft |
| cpe:2.3:a:microsoft:office_2024:-:*:*:*:ltsc:-:x64:* | not specified by NVD | Vulnerable | Microsoft |
| cpe:2.3:a:microsoft:office_2024:-:*:*:*:ltsc:-:x86:* | not specified by NVD | Vulnerable | Microsoft |
| cpe:2.3:a:microsoft:office_2024:-:*:*:*:ltsc:macos:-:* | not specified by NVD | Vulnerable | Microsoft |
| cpe:2.3:a:microsoft:office_online_server:*:*:*:*:*:*:*:* | before 16.0.10417.20228 | Vulnerable | Microsoft |
- 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
Microsoft 365 Apps for Enterprise is fixed through the updates listed on Microsoft's Office security releases page. Microsoft Office 365 for Mac, Microsoft Office LTSC for Mac 2021 and Microsoft Office LTSC for Mac 2024 are fixed in 16.114.26101123. Microsoft Office LTSC 2021 is fixed in 16.0.14334.20974, Microsoft Office LTSC 2024 is fixed in 16.0.17932.21056, and Office Online Server is fixed in 16.0.10417.20228 per KB5002928.
Written with Claude Haiku 5.5 from the sources below · 2026-10-28
Microsoft 1 update
- Security Update
- Office Online Server 16.0.10417.20228
Vendor assessments
Microsoft
Microsoft's page for this CVE →
- Impact
- Remote Code Execution
- Exploited
- No
- Publicly disclosed
- No
- Exploitability
- Exploitation Less Likely
| Product | Status | Plan or fix |
|---|---|---|
| Microsoft 365 Apps for Enterprise for 32-bit Systems | Fixed | https · //aka.ms/OfficeSecurityReleases |
| Microsoft 365 Apps for Enterprise for 64-bit Systems | Fixed | https · //aka.ms/OfficeSecurityReleases |
| Microsoft Office 365 for Mac | Fixed | 16.114.26101123 · Security Update |
| Microsoft Office LTSC 2021 for 32-bit editions | Fixed | 16.0.14334.20974 · Security Update |
| Microsoft Office LTSC 2021 for 64-bit editions | Fixed | 16.0.14334.20974 · Security Update |
| Microsoft Office LTSC 2024 for 32-bit editions | Fixed | 16.0.17932.21056 · Security Update |
| Microsoft Office LTSC 2024 for 64-bit editions | Fixed | 16.0.17932.21056 · Security Update |
| Microsoft Office LTSC for Mac 2021 | Fixed | 16.114.26101123 · Security Update |
| Microsoft Office LTSC for Mac 2024 | Fixed | 16.114.26101123 · Security Update |
Timeline
- 2026-10-13 Threatist record created from CVE-2026-97777
- 2026-10-13 Alias added: GHSA-7vxf-hw4v-f2h7
- 2026-10-14 Priority changed: LOW → MEDIUM
- 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
- 2026-10-16 Fix available: KB5002928 · Microsoft
References
More Microsoft 365 Apps vulnerabilities
- 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
Sources
- CVE-2026-97777 · CVE Program
- CVE-2026-97777 · NVD
- FIRST EPSS
- GHSA-7vxf-hw4v-f2h7 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-97777 · Microsoft Security Update Guide
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences