Reference page — cumulative record through Saturday, October 3, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
CVE-2026-78510
Microsoft Outlook and Word Remote Code Execution Vulnerability
AV AC PR UI S C I A CVSS EPSS %ile KEV
L L N N U H H H 8.4 .0034 25.4 —
AFFECTED
Product Versions Fixed
Microsoft 365 Apps for Enterprise 16.0.1 – —
Microsoft Office 2016 16.0.0 – —
Microsoft Office 2019 19.0.0 – —
Microsoft Office 365 for Mac 1.0.0 – —
Microsoft Office LTSC 2021 16.0.1 – —
Microsoft Office LTSC 2024 16.0.0 – —
Microsoft Office LTSC for Mac 2021 16.0.1 – —
Microsoft Office LTSC for Mac 2024 16.0.0 – —
TIMELINE
Aug 24 Reserved by microsoft
Sep 8 Published (CNA: microsoft)
Sep 25 RESCORED — CVE-2026-78510 (Microsoft 365 Apps for Enterprise). CVSS 9.8 → 8.4 (NVD).
Description
Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.
Lifecycle
Complete event history — 3 events, chronological
| Date | Event | Detail |
|---|
| August 24, 2026 | Reserved | Reserved by microsoft |
| September 8, 2026 | Published | Published (CNA: microsoft) |
| September 25, 2026 | RESCORED | RESCORED — CVE-2026-78510 (Microsoft 365 Apps for Enterprise). CVSS 9.8 → 8.4 (NVD). |
Affected
Affected products and packages — 8 rows
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
|---|
| Microsoft | Microsoft 365 Apps for Enterprise | — | 16.0.1 | — |
| Microsoft | Microsoft Office 2016 | — | 16.0.0 | — |
| Microsoft | Microsoft Office 2019 | — | 19.0.0 | — |
| Microsoft | Microsoft Office 365 for Mac | — | 1.0.0 | — |
| Microsoft | Microsoft Office LTSC 2021 | — | 16.0.1 | — |
| Microsoft | Microsoft Office LTSC 2024 | — | 16.0.0 | — |
| Microsoft | Microsoft Office LTSC for Mac 2021 | — | 16.0.1 | — |
| Microsoft | Microsoft Office LTSC for Mac 2024 | — | 16.0.0 | — |
About this page
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-78510 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Saturday, October 3, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.
