CVE-2026-44820
Integer underflow (wrap or wraparound) in Microsoft Office Excel allows an unauthorized attacker to execute code locally.
CSIRTS triage
- What
- This vulnerability allows an unauthorized attacker to execute code locally via an integer underflow.
- Who is affected
- Deployments of Microsoft Excel.
- Urgency
- Remediation is high urgency due to the high severity rating.
- Action
- Patch Microsoft Excel for CVE-2026-44820.
AI-assisted analysis generated from the source advisory — verify against the original.
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Exploitation outlook
- Low exploitation risk0.37% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 29% of all EPSS-scored CVEs.
Advisory coverage (1)
- highCVE-2026-44820: Microsoft Excel Remote Code Execution Vulnerabilitymsrc · 2026-06-09
External references
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[](https://www.csirts.com/cve/CVE-2026-44820)