EUVD-2026-56429
GHSA-pc5m-wcc8-vwh5
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Local file-open trigger requires user interaction but no system privileges; full impact on victim system 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
Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.
AnalysisAI
Heap-based buffer overflow in Microsoft Office enables local code execution when a user opens a specially crafted document, affecting multiple product lines including Office 2016 through Microsoft 365 Apps for Enterprise. The vulnerability carries a CVSS 7.8 (High) score and achieves full confidentiality, integrity, and availability compromise on the victim system. …
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 open a specially crafted Office document using an affected version of Microsoft Office (Office 2016 through Microsoft 365 Apps for Enterprise). … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 7.8 score reflects high real-world severity: full C/H/I/H/A/H impact, low complexity, and no privilege prerequisite on the victim system (PR:N). … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker crafts a malicious Office document exploiting the heap buffer overflow in the document parser and delivers it to a target via a phishing email or compromised file-sharing link. When the victim opens the file in an affected version of Microsoft Office, the malformed content triggers the heap overflow, corrupting memory structures and redirecting execution to attacker-controlled shellcode. … |
| Remediation | Apply the vendor-released patch via Microsoft Update or the Office Security Releases page at https://aka.ms/OfficeSecurityReleases. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, identify all Microsoft Office 2016 and Microsoft 365 Apps for Enterprise installations organization-wide and assess user criticality. …
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