CVE-2026-55055: Microsoft Word Remote Code Execution Vulnerability

highCVSS 7.8CVE-2026-55055

Stack-based buffer overflow in Microsoft Office Word allows an unauthorized attacker to execute code locally.

CSIRTS triage

vendor: Microsoft product: Microsoft Word Remote code execution

What: Stack-based buffer overflow in Microsoft Office Word allows an unauthorized attacker to execute code locally.
Who is affected: Users of Microsoft Office Word.
Urgency: Remediation is high urgency due to the potential for remote code execution.
Action: Update to the latest version of Microsoft Word to patch the vulnerability.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: high — CVSS 7.8
Published: 2026-07-14
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55055

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-2026-550550.37% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 30% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-55055	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 products (July 15, 2026)cert-fr-avis
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-2026-55055: Stack-based buffer overflow in Microsoft Office Word allows an unauthorized attacker to execut…nvd

Recent advisories for Microsoft Word Remote

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

highCVE-2026-55134: Microsoft Word Remote Code Execution Vulnerabilitymsrc · 2026-07-14
highCVE-2026-55032: Microsoft Word Remote Code Execution Vulnerabilitymsrc · 2026-07-14
highCVE-2026-55127: Microsoft Word Remote Code Execution Vulnerabilitymsrc · 2026-07-14
highCVE-2026-55130: Microsoft Word Remote Code Execution Vulnerabilitymsrc · 2026-07-14
highCVE-2026-55132: Microsoft Word Remote Code Execution Vulnerabilitymsrc · 2026-07-14
highCVE-2026-55033: Microsoft Word Remote Code Execution Vulnerabilitymsrc · 2026-07-14