EUVD-2026-56453
GHSA-qjh2-cff4-qrcf
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Local file-open trigger with no attacker privileges required; user must open the file; full CIA impact once exploited.
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
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 victim opens a maliciously crafted file. The vulnerability (CWE-122) corrupts heap memory in Excel's parsing logic, allowing an attacker to achieve full control over confidentiality, integrity, and availability of the affected system. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires the victim to open a maliciously crafted Excel file - this is the sole prerequisite established by the CVSS UI:R metric. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 score of 7.8 with vector AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H reflects a high-severity but locally-triggered vulnerability: exploitation requires the victim to open a malicious Excel file, which is a realistic social engineering vector but not remotely exploitable without user interaction. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker crafts a malicious Excel file containing a document structure designed to trigger the heap buffer overflow during parsing. The file is delivered via phishing email or malicious download, and when the victim opens it in Excel, the overflow corrupts heap memory, redirecting execution to attacker-controlled code with the privileges of the logged-in user. … |
| Remediation | Apply the patch released by Microsoft via the MSRC advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-68794. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours: Identify and inventory all systems running Excel and alert users to restrict opening documents from untrusted sources; block legacy .xls file formats via email gateway rules if possible. …
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Same weakness CWE-122 – Heap-based Buffer Overflow
View allSame technique Heap Overflow
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External POC / Exploit Code
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