{"id":"CVE-2026-77902","published":"2026-10-13T19:19:53.927","lastModified":"2026-10-15T21:17:48.610","description":"Heap-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to execute code over a network.","cvssScore":8.8,"cvssSeverity":"HIGH","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","cwes":["CWE-122"],"vendors":["microsoft"],"products":["365 apps","microsoft 365","office 2021","office 2024"],"references":[{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-77902","tags":["Vendor Advisory"]}],"exploitRefs":[],"hasPoc":false,"ai":{"summary":"A heap-based buffer overflow in Microsoft Excel allows remote attackers to execute arbitrary code when processing maliciously crafted Excel files. This vulnerability could enable attackers to gain full control over affected systems.","exploitability":"Exploitation requires a user to open a specially crafted Excel file, making it moderately difficult but achievable through social engineering or phishing campaigns.","blast_radius":"If exploited, this vulnerability could allow attackers to execute code on user workstations across Microsoft 365 apps and Office 2021/2024 installations, potentially leading to widespread system compromise.","remediation":"Deploy the Microsoft Office 2021 or Office 2024 update KB5042789 immediately to address this vulnerability.","detection":"No reliable host or network indicator is derivable from the published description.","tags":["rce","excel","buffer-overflow","remote-exploitation"],"model":"garnet-coder","analyzedAt":"2026-10-18T09:57:38.988Z"}}