CVE-2026-83778: Microsoft Internet Messaging API Remote Code Execution Vulnerability
Heap-based buffer overflow in Microsoft Internet Messaging API allows an unauthorized attacker to execute code over a network.
Other sources
Microsoft Internet Messaging API Remote Code Execution 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 10.0.26100.33650Patch KB5126646 - Upgrade
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Fixed in 6.2.9200.26434Patch KB5126835 - Upgrade
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Fixed in 10.0.26300.9711Patch KB5127648 - Upgrade
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Fixed in 10.0.14393.9612Patch KB5126868 - Upgrade
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Fixed in 6.3.9600.23470Patch KB5126836 - Upgrade
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Fixed in 10.0.17763.9376Patch KB5126651 - Upgrade
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Fixed in 10.0.22631.7652Patch KB5126653 - Upgrade
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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 10.0.26100.9711Patch KB5127648 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.19044.7807Patch KB5126657 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.20348.5761Patch KB5126655
Event History
Frequently Asked Questions
Which systems should be prioritized for investigation?
Systems running any of the listed Microsoft Windows client or server versions should be prioritized, especially hosts that can receive attacker-controlled network traffic involving the Microsoft Internet Messaging API. The vulnerability is rated high severity with network attack vector, no required privileges, and high potential impact to confidentiality, integrity, and availability.
Does exploitation require an authenticated account or user interaction?
The provided vector indicates that an attacker does not need privileges or authentication. However, user interaction is required, so exploitation depends on a user performing an unspecified action.
What is the likely impact if exploitation succeeds?
A successful heap-based buffer overflow can allow an attacker to execute code on the affected system. The supplied severity vector indicates high impact to confidentiality, integrity, and availability.