CVE-2026-63521
MEDIUMCVSS 5.5/10EPSS 0.37%
Last modified
CVE-2026-63521 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. Out-of-bounds read in Microsoft Office Word allows an unauthorized attacker to disclose information locally.. EPSS estimates a 0.37% chance of exploitation in the next 30 days.
Description
Out-of-bounds read in Microsoft Office Word allows an unauthorized attacker to disclose information locally.
Metrics
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Weakness Enumeration
Affected Software
Source: CNA advisory (CVE.org). NVD analysis pending.
| Vendor | Product | Versions |
|---|---|---|
| Microsoft | Microsoft 365 Apps for Enterprise | >= 16.0.1, < https://aka.ms/OfficeSecurityReleases |
| Microsoft | Microsoft Office 2019 | >= 19.0.0, < https://aka.ms/OfficeSecurityReleases |
| Microsoft | Microsoft Office LTSC 2021 | >= 16.0.1, < https://aka.ms/OfficeSecurityReleases |
| Microsoft | Microsoft Office LTSC 2024 | >= 16.0.0, < https://aka.ms/OfficeSecurityReleases |
| Microsoft | Microsoft Word 2016 | >= 16.0.1, < 16.0.5565.1000 |
References
Timeline
- Published
- Last Modified
- Status
- Undergoing Analysis
Frequently Asked Questions
What is CVE-2026-63521?
Out-of-bounds read in Microsoft Office Word allows an unauthorized attacker to disclose information locally.
How severe is CVE-2026-63521?
CVE-2026-63521 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.37% probability of exploitation in the next 30 days.
How do I fix CVE-2026-63521?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
Related CVEs from 2026
- CVE-2026-63516Deserialization of untrusted data in Microsoft Office ShareP…6.5
- CVE-2026-63517Out-of-bounds read in Microsoft Office allows an unauthorize…5.5
- CVE-2026-63518Heap-based buffer overflow in Microsoft Office Word allows a…7.8
- CVE-2026-63519Heap-based buffer overflow in Microsoft Office allows an una…7.8
- CVE-2026-6352GitLab has remediated an issue in GitLab EE affecting all ve…2.7
- CVE-2026-63520Improper input validation in Microsoft Office SharePoint all…8.1
- CVE-2026-63522Incorrect permission assignment for critical resource in Azu…7.8
- CVE-2026-63524Out-of-bounds read in Microsoft Office allows an unauthorize…5.5
- CVE-2026-63525Numeric truncation error in Microsoft Office Word allows an …7.8
- CVE-2026-63526Stack-based buffer overflow in Microsoft Office allows an un…7.8
- CVE-2026-63527Stack-based buffer overflow in Microsoft Office Word allows …7.8
- CVE-2026-63528Out-of-bounds read in Microsoft Office Word allows an unauth…5.5
Are you affected by CVE-2026-63521?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST