CVE-2026-45463: 365 Apps Stack Buffer Overflow (CVSS 8.4)
CVE-2026-45463 is a high-severity vulnerability rated 8.4/10 on the CVSS scale. Integer underflow (wrap or wraparound) in Microsoft Office allows an unauthorized attacker to execute code locally. EPSS estimates a 0.34% chance of exploitation in the next 30 days.
Description
Integer underflow (wrap or wraparound) in Microsoft Office allows an unauthorized attacker to execute code locally.
Metrics
CVSS 3.1 8.4/10
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Probability 0.34%
26.3th percentile
Probability of exploitation in the next 30 days. Learn more
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Microsoft | 365 Apps | All versions |
| Microsoft | 365 Copilot | All versions |
| Microsoft | Microsoft 365 | All versions |
| Microsoft | Office 2016 | All versions |
| Microsoft | Office 2019 | All versions |
| Microsoft | Office 2021 | All versions |
| Microsoft | Office 2024 | All versions |
References
Timeline
Published Jun 9, 2026
Last Modified Jul 23, 2026
Status Modified
Frequently Asked Questions
What is CVE-2026-45463?
Integer underflow (wrap or wraparound) in Microsoft Office allows an unauthorized attacker to execute code locally.
How severe is CVE-2026-45463?
CVE-2026-45463 has a CVSS score of 8.4/10 (HIGH severity). The EPSS model estimates a 0.34% probability of exploitation in the next 30 days.
How do I fix CVE-2026-45463?
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.
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Source: NVD / NIST