MicrosoftCVE-2026-55017
Microsoft Office: heap buffer overflow
High7.8CVE-2026-55017 · Published Jul 14, 2026 · updated Jul 16, 2026
Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.
Affected versions
| Package | Affected | Fixed in |
|---|---|---|
| Microsoft 365 Apps for Enterprise Product | >= 16.0.1, < https://aka.ms/OfficeSecurityReleases | https://aka.ms/OfficeSecurityReleases |
| Microsoft Office 2016 Product | >= 16.0.0, < 16.0.5561.1000 | 16.0.5561.1000 |
| Microsoft Office 2019 Product | >= 19.0.0, < https://aka.ms/OfficeSecurityReleases | https://aka.ms/OfficeSecurityReleases |
| Microsoft Office LTSC 2021 Product | >= 16.0.1, < https://aka.ms/OfficeSecurityReleases | https://aka.ms/OfficeSecurityReleases |
| Microsoft Office LTSC 2024 Product | >= 16.0.0, < https://aka.ms/OfficeSecurityReleases | https://aka.ms/OfficeSecurityReleases |
Details and references
- CVSS 3.1
- CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- Severity from
- the vendor (its own CVE record or advisory)
- Weakness
- CWE-122
More Microsoft advisories
All Microsoft| Date | Advisory | Severity | Fixed in |
|---|---|---|---|
| Jul 14 | Secret exfiltration vulnerability | High | 1.128.1 |
| Jul 14 | Workspace Trust Security Feature Bypass Vulnerability | High | 1.128.1 |
| Jul 14 | Remote Code Execution Vulnerability | High | 1.128.1 |
| Jul 14 | Microsoft .NET 8.0: unsafe deserialization | High7.8 | 8.0.29+9 more |
| Jul 14 | Microsoft .NET 8.0: code injection | High7.8 | 8.0.29+10 more |
| Jul 14 | Microsoft .NET 10.0: resource exhaustion | High7.5 | 10.0.10+5 more |