EUVD-2026-35661
GHSA-grp5-mh23-v8jr
Severity by source
AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
Lifecycle Timeline
3DescriptionCVE.org
Integer underflow (wrap or wraparound) in Microsoft Office Excel allows an unauthorized attacker to execute code locally.
AnalysisAI
Local code execution in Microsoft Office Excel can be achieved by an unauthenticated attacker who tricks a user into opening a malicious spreadsheet that triggers an integer underflow condition. The flaw carries a CVSS 7.0 rating reflecting high attack complexity and required user interaction, and no public exploit identified at time of analysis. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires the victim to open an attacker-controlled Excel workbook on their local system (AV:L combined with UI:R), so a delivery mechanism such as phishing or a drive-by download is mandatory. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 vector AV:L/AC:H/PR:N/UI:R indicates a locally-scored vulnerability requiring high attack complexity and user interaction but no privileges, with full CIA impact (C:H/I:H/A:H) producing the 7.0 base score. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker crafts a malicious Excel workbook designed to trigger the integer underflow / race condition during parsing and delivers it via spear-phishing email or a malicious download link. When the targeted user opens the file (and dismisses Protected View if it appears), the corrupted parsing state allows arbitrary code execution in the context of the Excel process, giving the attacker a foothold for credential theft, lateral movement, or ransomware staging. … |
| Remediation | Apply the Microsoft security update for Excel as listed on the MSRC advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-44818; exact fix build numbers are not present in the provided input and should be taken from that advisory. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours: Issue organization-wide security alert to all Excel users; enforce macro security settings to "Disable all macros with notification" via Group Policy. …
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Same weakness CWE-362 – Race Condition
View allSame technique Authentication Bypass
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External POC / Exploit Code
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