EUVD-2026-44186
GHSA-7w65-7pmj-m7w2
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Local file-open vector (AV:L, UI:R) with no privileges needed (PR:N); memory-corruption code execution yields full C:H/I:H/A:H in the user's context, matching the vendor score.
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
2DescriptionCVE.org
Heap-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to execute code locally.
AnalysisAI
Local code execution in Microsoft Excel (and the broader Office family including Microsoft 365 Apps for Enterprise, Office 2019/2021/2024 LTSC, Office for Mac, and Office Online Server) stems from a heap-based buffer overflow that triggers when a user opens a maliciously crafted spreadsheet. The CVSS vector (AV:L/AC:L/PR:N/UI:R) indicates an unauthenticated attacker gains full code execution in the victim's context but only after the target opens the file. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires the victim to open an attacker-supplied, maliciously crafted Excel/Office document in a vulnerable build (UI:R in the CVSS vector), and the attacker needs no prior authentication or privileges on the target (PR:N). … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 base score is 7.8 (High) with AV:L (local), AC:L (low complexity), PR:N (no privileges), UI:R (user interaction required), and full C:H/I:H/A:H impact - the classic 'open a weaponized document' profile. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker emails or hosts a specially crafted Excel spreadsheet and lures a victim into opening it (e.g., a spearphishing message with a business-themed attachment). Because AC:L and UI:R apply, opening the file with a vulnerable Office build triggers the heap overflow and runs attacker code in the user's security context with no elevation required. … |
| Remediation | Apply the Microsoft security update referenced in MSRC advisory CVE-2026-55041 (https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55041) - Patch available per vendor advisory; the exact fixed build numbers are published per channel in that advisory and should be pulled directly from it rather than assumed. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, inventory which Microsoft Office versions (365, 2019, 2021, 2024 LTSC, Mac) are deployed across the organization and identify affected users; issue a security advisory instructing users to avoid opening spreadsheets from untrusted sources and report suspicious files. …
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Arbitrary code execution in Microsoft PowerPoint (and the broader Microsoft Office/365 suite on Windows and macOS) arise
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Local code execution in Microsoft Office PowerPoint (CWE-122 heap-based buffer overflow) lets an unauthorized attacker r
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Local code execution in Microsoft Office (2016, 2019, LTSC 2021/2024, Microsoft 365 Apps, and Office for Mac 2021/2024)
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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