EUVD-2026-56760
GHSA-3w9w-7h4m-fvmr
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Local vector with user interaction matches document-delivery exploit pattern; full CIA impact from unrestricted code execution in user context.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
3DescriptionCVE.org
Heap-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to execute code locally.
AnalysisAI
Heap-based buffer overflow in Microsoft Office Excel enables local code execution when a user opens a specially crafted Excel file. The vulnerability triggers during file parsing, allowing an attacker who can deliver a malicious document to execute arbitrary code with the privileges of the logged-in user. No KEV listing or public exploit code has been identified at time of analysis, but the local-execution-via-document vector makes this a meaningful phishing and spear-phishing enabler.
Technical ContextAI
CWE-122 (Heap-based Buffer Overflow) identifies the root cause: Excel's file parsing routines write beyond the bounds of a heap-allocated buffer when processing malformed input in a crafted spreadsheet. The CVSS vector AV:L/AC:L/PR:N/UI:R/S:U is consistent with the classic document-as-delivery-vehicle pattern, where exploitation occurs in the memory space of the Excel process on the victim's local machine. No CPE strings were provided, so exact affected build versions are not independently confirmed from this dataset; the Microsoft Security Response Center advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-68812 is the authoritative source for affected product scope.
RemediationAI
Apply the Microsoft security update addressing CVE-2026-68812 via Windows Update or the Microsoft Update Catalog; the exact patched build version was not included in the provided data and must be confirmed against the MSRC advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-68812. As a compensating control prior to patching, configure Protected View to open files from the internet and email attachments in read-only sandboxed mode, which prevents code execution even if the malicious file is opened - note this may disrupt workflows that rely on immediate editing of downloaded files. Additionally, consider enforcing Attack Surface Reduction (ASR) rules in Microsoft Defender to block Office applications from spawning child processes, which limits post-exploitation lateral movement even if the overflow is triggered.
Microsoft Outlook Remote Code Execution Vulnerability. Rated critical severity (CVSS 9.8), this vulnerability is remotel
Microsoft Excel Security Feature Bypass Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is no authenti
Microsoft Outlook Security Feature Bypass Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely
Microsoft Publisher Security Feature Bypass Vulnerability. Rated high severity (CVSS 7.3), this vulnerability is low att
Microsoft Office contains a security feature bypass (CVE-2026-21509, CVSS 7.8) where reliance on untrusted inputs in sec
Microsoft Office Word contains a security decision bypass (CVE-2026-21514, CVSS 7.8) through reliance on untrusted input
Microsoft Office Access Connectivity Engine Remote Code Execution Vulnerability. Rated high severity (CVSS 7.8), this vu
Microsoft Office Remote Code Execution Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is no authentic
Microsoft Excel Remote Code Execution Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is no authentica
Use-after-free vulnerability in Microsoft Office Word that allows local, unauthenticated attackers to execute arbitrary
Microsoft Excel Remote Code Execution Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely expl
Microsoft Office Elevation of Privilege Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is low attack
Same weakness CWE-122 – Heap-based Buffer Overflow
View allSame technique Buffer Overflow
View allShare
External POC / Exploit Code
Leaving vuln.today