CVE-2026-77898
highHeap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code over a network.
Vendor / product: Microsoft — 365 apps
Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code over a network.
CVSS
7.5
7.5 (CVSS v3.1)
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H Severity source: NVD CVSS v3.1 (secure@microsoft.com)
Timeline (UTC)
Published: 2026-09-08 18:20
Modified: 2026-09-17 20:18
NVD status: Analyzed
Last synced 2 days ago
Verified against the source API 2026-10-27 06:52 UTC
Exploitation
Not listed in CISA KEV (as of last catalog sync)
Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).
Affected products
microsoft / 365_apps all versions
microsoft / microsoft_365 all versions
microsoft / office_2019 all versions
microsoft / office_2021 all versions
microsoft / office_2024 all versions
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-77898
Patch / mitigation: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-77898
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-77898 secure@microsoft.com
Data sources
NVD CVE API 2.0 — fetched 2026-10-27 06:52 UTC · record ↗