CVE-2026-21241 is a high-severity vulnerability that affects the Windows Ancillary Function Driver for WinSock. It allows an authorized attacker to elevate privileges locally. Given its nature, this vulnerability poses significant risks to organizations that rely on the affected systems. The vulnerability has been assigned a CVSS score of 7, which indicates a high level of risk.
Organizations should prioritize patching immediately. The potential impact of exploitation includes unauthorized access and control over sensitive data, making it imperative to address this issue swiftly. As of now, there are no known exploits in the wild, but the characteristics of the vulnerability suggest that it could be leveraged by attackers if not remediated.
The vulnerability was published on February 10, 2026, and is currently classified as analyzed. Organizations using the affected versions should remain vigilant and ensure they implement the necessary patches provided by Microsoft to mitigate associated risks.
Risk to organizations includes potential elevation of privileges that can lead to further exploitation of the system. Given the high severity and the local attack vector, it is crucial for security teams to include this vulnerability in their immediate remediation plans.
Vulnerability Details
This vulnerability allows an authorized attacker to elevate privileges locally. The CVSS score of 7 signals a high severity level, indicating a significant threat to affected systems. The vulnerability affects several versions of Microsoft Windows, specifically Windows 11 23h2, 24h2, 25h2, and Windows Server 2022.
The vulnerability was disclosed on February 10, 2026, and is associated with CWE-416, which refers to use after free errors. Organizations using any of the affected versions should take immediate action to patch their systems.
Technical Analysis
The root cause of this vulnerability stems from a use after free condition in the Windows Ancillary Function Driver for WinSock. This design flaw allows attackers to exploit the vulnerability under local conditions, requiring low privileges and no user interaction. Attack complexity is rated as high, meaning that successful exploitation may require specific conditions.
The impacts of this vulnerability are substantial, affecting confidentiality, integrity, and availability, all rated as high. If exploited, an attacker could gain elevated privileges, compromising sensitive data and potentially taking control of the system.
Risk & Impact Analysis
Real-world deployment risk is significant, particularly for organizations operating in environments where Windows systems are prevalent. Attackers may leverage this vulnerability to gain unauthorized access and control, leading to data breaches and potential financial loss.
Organizations should assess the blast radius of potential exploitation and prioritize patching based on the CVSS score and the impact of this vulnerability. Given its local attack vector and high complexity, security teams should take immediate action to mitigate risks.
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The following versions of Microsoft products are affected by CVE-2026-21241:
Windows 11 23h2 (all versions prior to 10.0.22631.6649), Windows 11 24h2 (all versions prior to 10.0.26100.7781), Windows 11 25h2 (all versions prior to 10.0.26200.7781), Windows Server 2022 (all versions prior to 10.0.20348.4711), Windows Server 2022 23h2 (all versions prior to 10.0.25398.2149), and Windows Server 2025 (all versions prior to 10.0.26100.32313).
Mitigation & Remediation
Organizations should apply the latest patches from Microsoft to remediate this vulnerability effectively. The recommended action is to upgrade to the latest versions of the affected products. For organizations unable to apply patches immediately, consider implementing configuration hardening and network controls to limit exposure.
Monitoring for unusual behavior and changes in system performance can help detect potential exploitation attempts while remediation efforts are underway. Regular reviews of the security posture in relation to this vulnerability are essential.
Organizations should validate remediation through penetration testing to ensure the effectiveness of applied patches and security measures.
Detection Guidance
Monitoring logs for indicators related to unauthorized access attempts and privilege escalations could provide early warning signs of exploitation. Behavioral anomalies, such as unexpected program crashes or unusual system behavior, should be investigated promptly.
Network signatures related to the Windows Ancillary Function Driver traffic may aid in identifying potential exploitation attempts. Keeping detailed records of system changes can also help trace back any incidents linked to this vulnerability.
AppSecure Threat Intelligence Insight
CVE-2026-21241 highlights a persistent issue in software security where vulnerabilities related to memory management continue to be exploited. Monitoring for similar patterns in software development can enhance the security posture.
Security teams should focus on addressing the root causes of such vulnerabilities by implementing secure coding practices and conducting regular code reviews. This incident reinforces the importance of threat modeling and proactive vulnerability management.
For further insights into enhancing security measures, organizations may consider reviewing best practices for penetration testing methodology and integrating them into their security framework.
Finally, organizations must stay informed about emerging threats and vulnerabilities to adapt their defenses accordingly. Continuous engagement with the cybersecurity community can provide valuable insights into best practices and evolving threats.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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