CVE-2026-78439: Microsoft Office Graphics Component Remote Code Execution Vulnerability

highCVSS 8.8CVE-2026-78439

Stack-based buffer overflow in Microsoft Graphics Component allows an unauthorized attacker to execute code over a network.

Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: high — CVSS 8.8
Published: 2026-09-08
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-78439

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-2026-784390.62% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 48% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-78439	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

Recent advisories for Microsoft Office Graphics

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-2026-65664: Microsoft Office Graphics Component Remote Code Execution Vulnerabilitymsrc · 2026-08-11
highCVE-2026-63519: Microsoft Office Graphics Component Remote Code Execution Vulnerabilitymsrc · 2026-08-11
mediumCVE-2026-62842: Microsoft Office Graphics Component Information Disclosure Vulnerabilitymsrc · 2026-08-11
highCVE-2026-63513: Microsoft Office Graphics Component Remote Code Execution Vulnerabilitymsrc · 2026-08-11
mediumCVE-2026-63517: Microsoft Office Graphics Component Information Disclosure Vulnerabilitymsrc · 2026-08-11
highCVE-2026-66807: Microsoft Office Graphics Component Remote Code Execution Vulnerabilitymsrc · 2026-08-11