EUVD-2026-56455
GHSA-3r5f-2f5q-hg58
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Local vector because file must be opened on device; no attacker privileges needed; user interaction mandatory; full impact triad consistent with arbitrary code execution.
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 Excel file. An unauthenticated attacker (per CVSS PR:N) delivers a malicious document that triggers the overflow upon interaction (UI:R), achieving full confidentiality, integrity, and availability compromise on the victim system. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires that the victim open a specially crafted Excel file - this is the sole prerequisite (UI:R in CVSS). … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 7.8 score reflects a serious but locally-triggered vulnerability: the local attack vector (AV:L) limits network-based mass exploitation, but the combination of no required privileges (PR:N), mandatory user interaction only (UI:R), and high impact across all three pillars (C:H/I:H/A:H) makes this a credible phishing and spear-phishing vehicle. … 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 that triggers a heap buffer overflow in Excel's parser. The file is delivered via a phishing email or malicious download; when the victim opens it, the overflow executes attacker-controlled code in the context of the logged-in user. … |
| Remediation | Apply the Microsoft security update addressing CVE-2026-68796 as documented in the MSRC update guide at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-68796. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
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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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