{"id":"CVE-2026-55949","title":"Microsoft Excel Remote Code Execution Vulnerability","summary":"Use of uninitialized resource in Microsoft Office Excel allows an unauthorized attacker to execute code locally.","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C","cvssSource":"cna","cwe":["CWE-908"],"vendor":"Microsoft","product":"Microsoft 365 Apps for Enterprise","affected":["365_apps_for_enterprise >= 16.0.1 < https://aka.ms/OfficeSecurityReleases","excel_2016 >= 16.0.0.0 < 16.0.5561.1001","office_2019 >= 19.0.0 < https://aka.ms/OfficeSecurityReleases","office_365_for_mac >= 1.0.0 < 16.111.26071215","office_ltsc_2021 >= 16.0.1 < https://aka.ms/OfficeSecurityReleases","office_ltsc_2024 >= 16.0.0 < https://aka.ms/OfficeSecurityReleases","office_ltsc_for_mac_2021 >= 16.0.1 < 16.111.26071215","office_ltsc_for_mac_2024 >= 16.0.0 < 16.111.26071215","office_online_server >= 16.0.0.0 < 16.0.10417.20175"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-07-15T03:56:08.802577Z"},"published":"2026-07-14","updated":"2026-09-17","sourceUpdated":"2026-09-17T22:33:10.438Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-55949","references":[{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55949","label":"Microsoft Excel Remote Code Execution Vulnerability"}],"tags":["cve.org"],"epss":0.00466,"epssPercentile":0.39472,"ingestedAt":"2026-09-08T17:06:31.907Z","slug":"CVE-2026-55949","body":"## Overview\n\nUse of uninitialized resource in Microsoft Office Excel allows an unauthorized attacker to execute code locally.\n\n## Affected\n\n- `365_apps_for_enterprise >= 16.0.1 < https://aka.ms/OfficeSecurityReleases`\n- `excel_2016 >= 16.0.0.0 < 16.0.5561.1001`\n- `office_2019 >= 19.0.0 < https://aka.ms/OfficeSecurityReleases`\n- `office_365_for_mac >= 1.0.0 < 16.111.26071215`\n- `office_ltsc_2021 >= 16.0.1 < https://aka.ms/OfficeSecurityReleases`\n- `office_ltsc_2024 >= 16.0.0 < https://aka.ms/OfficeSecurityReleases`\n- `office_ltsc_for_mac_2021 >= 16.0.1 < 16.111.26071215`\n- `office_ltsc_for_mac_2024 >= 16.0.0 < 16.111.26071215`\n- `office_online_server >= 16.0.0.0 < 16.0.10417.20175`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}