EUVD-2026-56754
GHSA-xvfh-c22c-fv36
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
AV:L reflects file-based exploitation requiring local document open; PR:N because no prior account privilege is needed; UI:R because victim must open the crafted workbook.
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 specially crafted file. The CVSS vector (AV:L/PR:N/UI:R) confirms exploitation requires no prior privileges but depends on user interaction - consistent with a malicious document delivery scenario. …
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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 (UI:R - confirmed by CVSS vector). … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 7.8 score reflects a meaningful but bounded threat: the local attack vector (AV:L) limits automated, internet-scale exploitation, and user interaction (UI:R) introduces a social engineering dependency that reduces attack success rates compared to zero-click vectors. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker crafts a malicious Excel workbook (.xlsx or .xls) that triggers the heap buffer overflow in Excel's parser and delivers it to a target via phishing email or a compromised file share. When the victim opens the file in an unpatched Excel installation, the overflow corrupts heap memory in a controlled manner, redirecting execution to attacker-supplied shellcode or ROP chain and granting the attacker code execution in the context of the victim's user account. … |
| Remediation | Apply the Microsoft security update published for CVE-2026-68798 via the MSRC update guide at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-68798. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, inventory all Excel installations and identify high-risk users handling sensitive documents; block Excel file receipt from external email immediately. …
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Threat intelligence, references, and detailed analysis are available after sign-in.
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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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