CVE-2026-55029: Microsoft Excel Remote Code Execution Vulnerability
Heap-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to execute code locally.
CSIRTS triage
- What
- Heap-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to execute code locally.
- Who is affected
- Unauthorized users of Microsoft Excel.
- Urgency
- Remediation is high urgency due to the potential for remote code execution.
- Action
- Update Microsoft Excel to the latest version.
AI-assisted analysis generated from the source advisory — verify against the original.
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Details
Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55029
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Low exploitation riskCVE-2026-550290.30% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 23% of all scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-55029 | coverage & exploitation status | NVD · CVE.org |
Same CVEs, other sources
How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.
- critical[NEW] [critical] Microsoft Office products: Multiple vulnerabilitiescert-bund
- unknownexploitedNCSC-2026-0237 [1.02] [H/H] Vulnerabilities Fixed in Microsoft Officencsc-nl
- unknownexploitedNCSC-2026-0237 [1.01] [H/H] Vulnerabilities fixed in Microsoft Officencsc-nl
- unknownMultiple vulnerabilities in Microsoft Office (July 15, 2026)cert-fr-avis
- unknownexploitedNCSC-2026-0237 [1.00] [M/H] Vulnerabilities fixed in Microsoft Officencsc-nl
- highCVE-2026-55029: Heap-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to execut…nvd
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