EUVD-2026-56459
GHSA-5wr6-m8x4-v27m
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
File parsed locally (AV:L, UI:R); attacker needs no system account (PR:N); successful exploitation yields full code execution in victim context (C:H/I:H/A:H).
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Lifecycle Timeline
3DescriptionCVE.org
Out-of-bounds write in Microsoft Office Excel allows an unauthorized attacker to execute code locally.
AnalysisAI
Out-of-bounds write (CWE-787) in Microsoft Office Excel enables local code execution when a user opens a specially crafted Excel file, yielding full confidentiality, integrity, and availability impact at CVSS 7.8. The attack is file-delivery based - typical phishing or drive-by download - requiring no system privileges from the attacker but requiring the victim to open the malicious document. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | The victim must actively open a specially crafted Excel file, making social engineering or phishing the required delivery mechanism - the CVSS UI:R metric confirms that exploitation cannot occur without this explicit user action. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 7.8 score (AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H) accurately reflects a high-severity, file-based exploit: no attacker privileges are required, attack complexity is low once the file reaches the victim, and the full CIA triad is compromised upon successful exploitation. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker crafts a malicious Excel workbook containing a specially structured record designed to trigger the out-of-bounds write in Excel's parser, then delivers it to the target via a phishing email or compromised download link. When the victim opens the file in an unpatched Excel installation, the parser corrupts memory and the attacker's shellcode executes in the context of the victim's user account. … |
| Remediation | Apply the update provided by Microsoft via Windows Update, Microsoft Update Catalog, or enterprise patch management tooling; the MSRC advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-68806 is the authoritative source for the specific package versions and update KB numbers. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, issue urgent user advisory against opening Excel files from external senders and deploy email filtering to block or quarantine suspicious Excel attachments. …
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Same weakness CWE-787 – Out-of-bounds Write
View allSame technique Memory Corruption
View allShare
External POC / Exploit Code
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