CVE-2026-78459: Microsoft Internet Information Services Elevation of Privilege Vulnerability
Heap-based buffer overflow in Windows Internet Information Services allows an authorized attacker to elevate privileges locally.
Other sources
Microsoft Internet Information Services Elevation of Privilege Vulnerability
— Microsoft
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.26300.9711Patch KB5127648 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 6.3.9600.23470Patch KB5126836 - Upgrade
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Fixed in 10.0.14393.9612Patch KB5126868 - Upgrade
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Fixed in 6.2.9200.26434Patch KB5126835 - Upgrade
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Fixed in 10.0.22631.7652Patch KB5126653 - Upgrade
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Fixed in 10.0.19044.7807Patch KB5126657 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.28000.3231Patch KB5127646 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.26200.9711Patch KB5127648 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.26100.33650Patch KB5126646 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.20348.5761Patch KB5126655 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.26100.9711Patch KB5127648 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.17763.9376Patch KB5126651
Event History
Frequently Asked Questions
Who can exploit this vulnerability?
An attacker must already be authorized on the affected system and able to execute an attack locally. The available information does not indicate that remote, unauthenticated exploitation is possible.
What impact could successful exploitation have?
Successful exploitation could allow elevation of privilege and affect confidentiality, integrity, and availability. The vulnerability is a heap-based buffer overflow in Internet Information Services.
Which systems should be reviewed?
Review systems running Microsoft Windows 10 or Windows 11, and Windows Server 2012, 2012 R2, 2016, 2019, 2022, or 2025 where Microsoft Internet Information Services is present.