365 Apps
CVE-2026-26109
HIGH
Severity by source
AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
Lifecycle Timeline
2DescriptionCVE.org
Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to execute code locally.
AnalysisAI
Arbitrary code execution in Microsoft Office Excel and related products (Office Online Server, 365 Apps) via out-of-bounds memory read allows local attackers to achieve complete system compromise without requiring user interaction or elevated privileges. This high-severity vulnerability affects multiple Microsoft Office components and currently lacks a security patch. An attacker with local access can exploit memory corruption to execute malicious code with full system permissions.
Technical ContextAI
Classified as CWE-125 (Out-of-bounds Read). Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to execute code locally.
RemediationAI
Monitor vendor advisories for a patch.
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Same weakness CWE-125 – Out-of-bounds Read
View allSame technique Buffer Overflow
View allShare
External POC / Exploit Code
Leaving vuln.today