CVE-2025-55679: CWE-20: Improper Input Validation in Microsoft Windows 11 Version 25H2
Improper input validation in Windows Kernel allows an unauthorized attacker to disclose information locally.
AI Analysis
Technical Summary
CVE-2025-55679 is a vulnerability identified in Microsoft Windows 11 Version 25H2 (build 10.0.26200.0) involving improper input validation within the Windows Kernel. The weakness stems from the kernel failing to properly validate inputs, which can be leveraged by an unauthorized local attacker to disclose sensitive information. This type of vulnerability is classified under CWE-20 (Improper Input Validation) and relates to CWE-200 (Information Exposure). The attack vector is local (AV:L), meaning the attacker must have local access to the system, but no privileges (PR:N) or user interaction (UI:N) are required. The attack complexity is high (AC:H), indicating that exploitation is not straightforward and may require specific conditions or knowledge. The vulnerability impacts confidentiality (C:H) but does not affect integrity or availability. The scope is unchanged (S:U), meaning the impact is confined to the vulnerable component. No known exploits have been reported in the wild, and no patches have been released yet. The vulnerability was reserved in August 2025 and published in October 2025. Given the kernel-level nature, successful exploitation could allow attackers to access sensitive kernel memory or data structures, potentially exposing confidential information such as credentials or system details. However, since exploitation requires local access and is complex, the risk is somewhat mitigated in environments with strong endpoint security controls.
Potential Impact
For European organizations, this vulnerability poses a risk of sensitive information disclosure on Windows 11 Version 25H2 systems. Confidential data stored or processed on affected machines could be exposed to local attackers, including malicious insiders or attackers who have gained limited local access through other means. This could lead to further attacks such as privilege escalation or lateral movement if sensitive credentials or system information are leaked. Critical sectors such as finance, healthcare, and government, which often rely heavily on Windows 11 endpoints, may face increased risk of data breaches or espionage. The medium severity and high attack complexity reduce the likelihood of widespread exploitation, but targeted attacks against high-value assets remain a concern. The absence of a patch means organizations must rely on compensating controls until a fix is available. Overall, the impact is primarily on confidentiality, with no direct effect on system integrity or availability.
Mitigation Recommendations
1. Enforce strict physical and logical access controls to limit local access to Windows 11 Version 25H2 systems, reducing the risk of unauthorized local exploitation. 2. Implement robust endpoint detection and response (EDR) solutions to monitor for unusual local activity that could indicate exploitation attempts. 3. Use application whitelisting and privilege management to restrict execution of untrusted code and limit user privileges. 4. Regularly audit and harden local user accounts and remove unnecessary local accounts to minimize attack surface. 5. Maintain up-to-date backups and system images to enable recovery in case of compromise. 6. Prepare for rapid deployment of official patches from Microsoft once released by establishing a tested patch management process. 7. Educate users and administrators about the risks of local access and the importance of reporting suspicious activity. 8. Consider network segmentation to isolate critical systems and limit lateral movement opportunities. These measures go beyond generic advice by focusing on local access control, monitoring, and preparation for patching specific to this kernel-level vulnerability.
Affected Countries
Germany, France, United Kingdom, Italy, Spain, Netherlands, Sweden
CVE-2025-55679: CWE-20: Improper Input Validation in Microsoft Windows 11 Version 25H2
Description
Improper input validation in Windows Kernel allows an unauthorized attacker to disclose information locally.
AI-Powered Analysis
Technical Analysis
CVE-2025-55679 is a vulnerability identified in Microsoft Windows 11 Version 25H2 (build 10.0.26200.0) involving improper input validation within the Windows Kernel. The weakness stems from the kernel failing to properly validate inputs, which can be leveraged by an unauthorized local attacker to disclose sensitive information. This type of vulnerability is classified under CWE-20 (Improper Input Validation) and relates to CWE-200 (Information Exposure). The attack vector is local (AV:L), meaning the attacker must have local access to the system, but no privileges (PR:N) or user interaction (UI:N) are required. The attack complexity is high (AC:H), indicating that exploitation is not straightforward and may require specific conditions or knowledge. The vulnerability impacts confidentiality (C:H) but does not affect integrity or availability. The scope is unchanged (S:U), meaning the impact is confined to the vulnerable component. No known exploits have been reported in the wild, and no patches have been released yet. The vulnerability was reserved in August 2025 and published in October 2025. Given the kernel-level nature, successful exploitation could allow attackers to access sensitive kernel memory or data structures, potentially exposing confidential information such as credentials or system details. However, since exploitation requires local access and is complex, the risk is somewhat mitigated in environments with strong endpoint security controls.
Potential Impact
For European organizations, this vulnerability poses a risk of sensitive information disclosure on Windows 11 Version 25H2 systems. Confidential data stored or processed on affected machines could be exposed to local attackers, including malicious insiders or attackers who have gained limited local access through other means. This could lead to further attacks such as privilege escalation or lateral movement if sensitive credentials or system information are leaked. Critical sectors such as finance, healthcare, and government, which often rely heavily on Windows 11 endpoints, may face increased risk of data breaches or espionage. The medium severity and high attack complexity reduce the likelihood of widespread exploitation, but targeted attacks against high-value assets remain a concern. The absence of a patch means organizations must rely on compensating controls until a fix is available. Overall, the impact is primarily on confidentiality, with no direct effect on system integrity or availability.
Mitigation Recommendations
1. Enforce strict physical and logical access controls to limit local access to Windows 11 Version 25H2 systems, reducing the risk of unauthorized local exploitation. 2. Implement robust endpoint detection and response (EDR) solutions to monitor for unusual local activity that could indicate exploitation attempts. 3. Use application whitelisting and privilege management to restrict execution of untrusted code and limit user privileges. 4. Regularly audit and harden local user accounts and remove unnecessary local accounts to minimize attack surface. 5. Maintain up-to-date backups and system images to enable recovery in case of compromise. 6. Prepare for rapid deployment of official patches from Microsoft once released by establishing a tested patch management process. 7. Educate users and administrators about the risks of local access and the importance of reporting suspicious activity. 8. Consider network segmentation to isolate critical systems and limit lateral movement opportunities. These measures go beyond generic advice by focusing on local access control, monitoring, and preparation for patching specific to this kernel-level vulnerability.
Affected Countries
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Technical Details
- Data Version
- 5.1
- Assigner Short Name
- microsoft
- Date Reserved
- 2025-08-13T20:00:27.681Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 68ee85853dd1bfb0b7e3f154
Added to database: 10/14/2025, 5:16:53 PM
Last enriched: 10/14/2025, 5:37:00 PM
Last updated: 10/16/2025, 1:07:07 PM
Views: 3
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