EUVD-2026-44219
GHSA-j39m-7jfm-44r6
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
File-open client RCE: local vector and required user interaction (AV:L/UI:R), no privileges needed (PR:N), full code execution yields total C/I/A impact.
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 OneNote allows an unauthorized attacker to execute code locally.
AnalysisAI
Local code execution in Microsoft Office OneNote (Microsoft 365 Apps for Enterprise and Office for Mac editions) arises from a heap-based buffer overflow (CWE-122) that lets an attacker run arbitrary code in the context of the current user when a victim opens a maliciously crafted OneNote file. The CVSS 3.1 score is 7.8 with a local attack vector requiring user interaction (AV:L/UI:R), and impact is total across confidentiality, integrity, and availability. …
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 | Exploitation requires a victim to open an attacker-supplied malicious OneNote file on an affected build (Microsoft 365 Apps for Enterprise or Office for Mac 2021/2024/365) - the CVSS UI:R metric confirms mandatory user interaction, which is the key limiting factor. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | Signals are moderately consistent and point to real-but-not-emergency priority. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker emails or shares a crafted OneNote document that triggers the heap overflow when parsed; a targeted user opens the file, and the malformed structure corrupts the heap to execute the attacker's code in the user's security context. Because the vector is local with required user interaction (AV:L/UI:R), the attack is realistically delivered via phishing or a watering-hole download rather than remotely without victim action. … |
| Remediation | Patch available per vendor advisory: apply the Microsoft Office/OneNote security update referenced at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55133 for your channel - Microsoft 365 Apps for Enterprise, Office 365 for Mac, and Office LTSC for Mac 2021/2024. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, inventory all OneNote installations across Microsoft 365 Apps for Enterprise and Office for Mac environments and assess file-sharing exposure in collaboration tools. …
Sign in for detailed remediation steps and compensating controls.
Threat intelligence, references, and detailed analysis are available after sign-in.
Local code execution in Microsoft Word (and Office/SharePoint components that render Word content) stems from an integer
Local code execution in Microsoft Office (2016, 2019, LTSC 2021/2024, Microsoft 365 Apps, and the macOS editions) arises
Arbitrary code execution in Microsoft Office Word (and the broader Office/365/SharePoint family) arises from a stack-bas
Local code execution in Microsoft Office (including Microsoft 365 Apps for Enterprise, Office 2016/2019, and Office LTSC
Local code execution in Microsoft Word (part of Microsoft 365 Apps, Office 2019, Office LTSC 2021/2024, and Office for M
Local arbitrary code execution in Microsoft Office (2016, 2019, LTSC 2021/2024, Microsoft 365 Apps for Enterprise, and O
Arbitrary code execution in Microsoft PowerPoint (and the broader Microsoft Office/365 suite on Windows and macOS) arise
Local code execution in Microsoft Office PowerPoint (including Microsoft 365 Apps, Office 2019, Office LTSC 2021/2024, a
Local code execution in Microsoft Office PowerPoint (CWE-122 heap-based buffer overflow) lets an unauthorized attacker r
Local code execution in Microsoft Word (and the wider Microsoft Office / Microsoft 365 Apps family) lets an unauthorized
Local code execution in Microsoft Office (2016, 2019, LTSC 2021/2024, Microsoft 365 Apps for Enterprise, and Office for
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
View allShare
External POC / Exploit Code
Leaving vuln.today