EUVD-2026-56456
GHSA-fg32-39rc-x8mq
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
File must be opened locally by the user (AV:L, UI:R); no attacker credentials needed (PR:N); heap overflow yields full code execution (C:H/I:H/A:H) within the user's process scope (S:U).
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 Excel file. The attack requires no privileges from the attacker but does require user interaction - consistent with a malicious document delivery vector - and carries high impact across confidentiality, integrity, and availability. …
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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 - user interaction is confirmed required by UI:R in the CVSS vector. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 7.8 score is well-calibrated for this class of vulnerability: AV:L confirms exploitation requires the file to be executed on the victim's machine, which limits opportunistic mass exploitation but is entirely consistent with targeted phishing or watering-hole delivery. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker crafts a malicious Excel workbook with a specially structured record that triggers a heap overflow in Excel's file parser and delivers it via a phishing email. When the targeted user opens the attachment, the corrupted heap enables shellcode execution in the context of the user's account, granting the attacker a foothold with the victim's privileges. … |
| Remediation | Apply the Microsoft security update published through the MSRC advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-68800 - the exact patched version is not confirmed in the available input data and must be verified there directly. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours: Conduct a rapid asset inventory of Excel installations across the enterprise and identify business-critical workflows dependent on Excel; activate email security controls to block or quarantine Excel file attachments from external senders. …
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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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