EUVD-2026-56705
GHSA-3r88-gh6h-7xh6
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Local file-parse trigger requires user to open file (UI:R, AV:L); no attacker privileges needed (PR:N); full code execution yields C:H/I:H/A:H with no scope change.
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
Integer overflow or wraparound in Microsoft Office allows an unauthorized attacker to execute code locally.
AnalysisAI
Local code execution in Microsoft Office stems from an integer overflow that cascades into a heap-based buffer overflow (CWE-122), affecting Office 2016 through LTSC 2024 on both Windows and macOS. An unauthenticated attacker who can convince a target user to open a crafted Office document gains full code execution with the victim's privilege level - achieving high confidentiality, integrity, and availability impact per the CVSS:3.1 AV:L/C:H/I:H/A:H rating. …
Unlock full vulnerability intelligence
- Risk assessment & exploitation conditions
- Attack chain visualization
- Remediation with exact patch versions
- Threat intelligence from 22 sources
- Personal watchlist & email alerts
Free forever · No credit card required
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | The victim must actively open a specially crafted Office document on a system running an unpatched version of Microsoft Office - this is the sole prerequisite, consistent with AV:L/UI:R in the CVSS vector. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS base score of 7.8 is consistent with a classic malicious-document exploitation scenario. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker crafts a malicious Office document - such as a .docx or .xlsx - engineered to trigger the integer wraparound during parsing of a specially sized data structure, causing a heap buffer overflow within the Office process. The document is delivered to a targeted employee via a phishing email or a compromised file-sharing link; when the victim opens the file in an unpatched Office installation, the overflow overwrites heap metadata or function pointers, redirecting execution to attacker-controlled shellcode running as the victim's user account. … |
| Remediation | Apply the vendor-released patch immediately. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, identify all endpoints running Microsoft Office 2016 through LTSC 2024 and implement file restrictions preventing Office documents from untrusted external sources from executing. …
Sign in for detailed remediation steps and compensating controls.
Threat intelligence, references, and detailed analysis are available after sign-in.
Microsoft Outlook Remote Code Execution Vulnerability. Rated critical severity (CVSS 9.8), this vulnerability is remotel
Microsoft Excel Security Feature Bypass Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is no authenti
Microsoft Publisher Security Feature Bypass Vulnerability. Rated high severity (CVSS 7.3), this vulnerability is low att
Microsoft Office contains a security feature bypass (CVE-2026-21509, CVSS 7.8) where reliance on untrusted inputs in sec
Microsoft Office Word contains a security decision bypass (CVE-2026-21514, CVSS 7.8) through reliance on untrusted input
Microsoft Office Access Connectivity Engine Remote Code Execution Vulnerability. Rated high severity (CVSS 7.8), this vu
Microsoft Office Remote Code Execution Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is no authentic
Microsoft Excel Remote Code Execution Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is no authentica
Use-after-free vulnerability in Microsoft Office Word that allows local, unauthenticated attackers to execute arbitrary
Microsoft Excel Remote Code Execution Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely expl
Microsoft Office Elevation of Privilege Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is low attack
A remote code execution vulnerability exists in Microsoft Excel software when the software fails to properly handle obje
Same weakness CWE-122 – Heap-based Buffer Overflow
View allSame technique Heap Overflow
View allShare
External POC / Exploit Code
Leaving vuln.today