Microsoft IIS Flaw Enables Remote Code Execution by Unauthorized Attackers

A newly disclosed vulnerability in Internet Information Services (IIS) Inbox COM Objects could allow attackers to execute arbitrary code on affected systems.

Tracked as CVE-2025-59282, the flaw stems from a race condition and use-after-free scenario in shared memory components.

Microsoft assigned itself as the CNA and rated the issue as Important, with a CVSS 3.1 score of 7.0 (temporal 6.1) based on local attack vector, high complexity, no required privileges, and user interaction.

Race Condition in Inbox COM Objects

The vulnerability arises from concurrent execution on a global memory resource used by certain IIS COM objects. In a race condition (CWE-362), improper synchronization lets one thread free memory that another thread still uses (CWE-416), creating a window for use-after-free exploitation.

An attacker can craft a malicious file and trick a local user into opening it. If the race is won, arbitrary code runs with elevated trust on the same machine, potentially granting shell access or the ability to drop additional payloads.

• Attack requires precise timing to exploit the synchronization flaw.
• Involves both race condition and use-after-free vulnerabilities.
• Relies on user opening a specially crafted file.

Understanding these technical details helps defenders anticipate and recognize suspicious file executions.

Attack Complexity and Mitigation Strategies

Despite being labeled Remote Code Execution, exploitation is strictly local: an attacker must already have code execution capabilities on the target host or persuade a legitimate user to load a specially crafted component.

The CVSS vector string CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H underscores this nuance: the attack complexity is high, requiring precise timing to win the race, and user interaction is mandatory.

No known public exploit or widespread weaponization exists, and Microsoft assesses real-world exploitation as unlikely at present.

• Systems without IIS enabled remain unaffected.
• Disabling legacy COM object support reduces attack surface.
• Application whitelisting can prevent untrusted file execution.

Until an official patch is applied, these mitigations provide layered defenses against potential exploitation.

Microsoft’s Response and Recommendations

Microsoft released an official fix on October 14, 2025, within its regular security update cycle. All supported versions of Windows Server running IIS should install the update immediately to remediate CVE-2025-59282.

Organizations are encouraged to review their software inventory for IIS installations and confirm that inbox COM object features are disabled unless explicitly needed.

Regularly monitoring the Microsoft Support Lifecycle portal ensures that patches are applied promptly to maintain a hardened environment against coordinated vulnerability disclosures.

Staying current with security bulletins and reinforcing local security policies remains essential, as emerging vulnerabilities like this one continue to target underlying synchronization flaws in legacy components.

Product	Release Date	Impact	Severity	KB Article(s)	Download Link	Build Number
Windows 11 Version 25H2 (x64)	Oct 14, 2025	Remote Code Execution	Important	5066835	Security Update	10.0.26200[.]6899
Windows 11 Version 25H2 (ARM64)	Oct 14, 2025	Remote Code Execution	Important	5066835	Security Update	10.0.26200[.]6899
Windows Server 2012 R2 (Server Core)	Oct 14, 2025	Remote Code Execution	Important	5066873	Monthly Rollup	6.3.9600[.]22824
Windows Server 2012 R2	Oct 14, 2025	Remote Code Execution	Important	5066873	Monthly Rollup	6.3.9600[.]22824
Windows Server 2012 (Server Core)	Oct 14, 2025	Remote Code Execution	Important	5066875	Monthly Rollup	6.2.9200[.]25722
Windows Server 2012	Oct 14, 2025	Remote Code Execution	Important	5066875	Monthly Rollup	6.2.9200[.]25722
Windows Server 2008 R2 SP1 (Server Core, x64)	Oct 14, 2025	Remote Code Execution	Important	5066872, 5066876	Monthly Rollup / Security Only	6.1.7601[.]27974
Windows Server 2008 R2 SP1 (x64)	Oct 14, 2025	Remote Code Execution	Important	5066872, 5066876	Monthly Rollup / Security Only	6.1.7601[.]27974
Windows Server 2008 SP2 (Server Core, x64)	Oct 14, 2025	Remote Code Execution	Important	5066874, 5066877	Monthly Rollup / Security Only	6.0.6003[.]23571
Windows Server 2008 SP2 (x64)	Oct 14, 2025	Remote Code Execution	Important	5066874, 5066877	Monthly Rollup / Security Only	6.0.6003[.]23571
Windows Server 2008 SP2 (Server Core, 32-bit)	Oct 14, 2025	Remote Code Execution	Important	5066874, 5066877	Monthly Rollup / Security Only	6.0.6003[.]23571
Windows Server 2008 SP2 (32-bit)	Oct 14, 2025	Remote Code Execution	Important	5066874, 5066877	Monthly Rollup / Security Only	6.0.6003[.]23571
Windows Server 2016 (Server Core)	Oct 14, 2025	Remote Code Execution	Important	5066836	Security Update	10.0.14393[.]8519
Windows Server 2016	Oct 14, 2025	Remote Code Execution	Important	5066836	Security Update	10.0.14393[.]8519
Windows 10 Version 1607 (x64)	Oct 14, 2025	Remote Code Execution	Important	5066836	Security Update	10.0.14393[.]8519
Windows 10 Version 1607 (32-bit)	Oct 14, 2025	Remote Code Execution	Important	5066836	Security Update	10.0.14393[.]8519
Windows 10 (x64)	Oct 14, 2025	Remote Code Execution	Important	5066837	Security Update	10.0.10240[.]21161
Windows 10 (32-bit)	Oct 14, 2025	Remote Code Execution	Important	5066837	Security Update	10.0.10240[.]21161
Windows Server 2025	Oct 14, 2025	Remote Code Execution	Important	5066835	Security Update	10.0.26100[.]6899
Windows 11 Version 24H2 (x64)	Oct 14, 2025	Remote Code Execution	Important	5066835	Security Update	10.0.26100[.]6899
Windows 11 Version 24H2 (ARM64)	Oct 14, 2025	Remote Code Execution	Important	5066835	Security Update	10.0.26100[.]6899
Windows Server 2022 23H2 (Server Core)	Oct 14, 2025	Remote Code Execution	Important	5066780	Security Update	10.0.25398[.]1913
Windows 11 Version 23H2 (x64)	Oct 14, 2025	Remote Code Execution	Important	5066793	Security Update	10.0.22631[.]6060
Windows 11 Version 23H2 (ARM64)	Oct 14, 2025	Remote Code Execution	Important	5066793	Security Update	10.0.22631[.]6060
Windows Server 2025 (Server Core)	Oct 14, 2025	Remote Code Execution	Important	5066835	Security Update	10.0.26100[.]6899
Windows 10 Version 22H2 (32-bit)	Oct 14, 2025	Remote Code Execution	Important	5066791	Security Update	10.0.19045[.]6456
Windows 10 Version 22H2 (ARM64)	Oct 14, 2025	Remote Code Execution	Important	5066791	Security Update	10.0.19045[.]6456
Windows 10 Version 22H2 (x64)	Oct 14, 2025	Remote Code Execution	Important	5066791	Security Update	10.0.19045[.]6456
Windows 11 Version 22H2 (x64)	Oct 14, 2025	Remote Code Execution	Important	5066793	Security Update	10.0.22621[.]6060
Windows 11 Version 22H2 (ARM64)	Oct 14, 2025	Remote Code Execution	Important	5066793	Security Update	10.0.22621[.]6060
Windows 10 Version 21H2 (x64)	Oct 14, 2025	Remote Code Execution	Important	5066791	Security Update	10.0.19044[.]6456
Windows 10 Version 21H2 (ARM64)	Oct 14, 2025	Remote Code Execution	Important	5066791	Security Update	10.0.19044[.]6456
Windows 10 Version 21H2 (32-bit)	Oct 14, 2025	Remote Code Execution	Important	5066791	Security Update	10.0.19044[.]6456
Windows Server 2022 (Server Core)	Oct 14, 2025	Remote Code Execution	Important	5066782	Security Update	10.0.20348[.]4294
Windows Server 2022	Oct 14, 2025	Remote Code Execution	Important	5066782	Security Update	10.0.20348[.]4294
Windows Server 2019 (Server Core)	Oct 14, 2025	Remote Code Execution	Important	5066586	Security Update	10.0.17763[.]7919
Windows Server 2019	Oct 14, 2025	Remote Code Execution	Important	5066586	Security Update	10.0.17763[.]7919
Windows 10 Version 1809 (x64)	Oct 14, 2025	Remote Code Execution	Important	5066586	Security Update	10.0.17763[.]7919
Windows 10 Version 1809 (32-bit)	Oct 14, 2025	Remote Code Execution	Important	5066586	Security Update	10.0.17763[.]7919

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The post Microsoft IIS Flaw Enables Remote Code Execution by Unauthorized Attackers appeared first on Cyber Security News.