EUVD-2026-56458
GHSA-mqxf-72vh-q4mh
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
File-based exploit requires local execution by victim (AV:L, UI:R), no attacker privileges needed (PR:N), with full system compromise on successful exploitation (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
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 file, granting full confidentiality, integrity, and availability compromise of the affected system. The CVSS vector (AV:L/AC:L/PR:N/UI:R) confirms this is a document-triggered exploit requiring no attacker privileges but demanding victim interaction - a profile consistent with malicious email attachment or drive-by download campaigns. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | The victim must actively open a specially crafted Microsoft Excel file - exploitation is triggered at parse time, not by enabling macros or interacting with content. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | CVSS 7.8 (High) reflects the severe C:H/I:H/A:H impact but is moderated by AV:L and UI:R - the attacker cannot reach this vulnerability over the network without the victim actively opening a file. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker crafts a malicious Excel spreadsheet (.xlsx or legacy .xls) designed to trigger the heap overflow during file parsing and delivers it via a spear-phishing email to a target user. When the victim opens the attachment in Microsoft Excel, the malformed file triggers the buffer overflow, enabling the attacker to execute arbitrary code under the victim's user context. … |
| Remediation | Apply the patch released by Microsoft via Windows Update or the Microsoft Update Catalog, referencing the MSRC advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-68807 for the specific KB article and fixed build version. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours: Alert all Excel users not to open documents from untrusted external sources; implement email filtering to block or quarantine Excel files from external senders; restrict Excel execution in email client and web browser contexts. …
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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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