CVE-2026-21238 is a high-severity vulnerability affecting the Windows Ancillary Function Driver for WinSock. This vulnerability allows an authorized attacker to elevate privileges locally, posing significant risks to affected systems. With a CVSS score of 7.8, it falls into the high severity category, indicating its potential impact on organizational security.
The existence of this vulnerability could lead to unauthorized access and control over sensitive resources, allowing attackers to manipulate system operations and potentially compromise data integrity and confidentiality. Organizations should take immediate action to assess their systems for vulnerabilities and prioritize remediation efforts.
The vulnerability was published on February 10, 2026, and has been analyzed for potential exploitation. Currently, no known exploits are confirmed in the wild, but the nature of the vulnerability warrants urgent attention from security teams.
To maintain a secure environment, organizations should prioritize patching immediately and ensure that their systems are updated to mitigate this vulnerability's impact.
Vulnerability Details
Improper access control in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally. The CVSS 3.1 score is 7.8, indicating high severity, with a local attack vector and low complexity. Affected products include various versions of Windows 10 and Windows Server.
Technical Analysis
The root cause of this vulnerability lies in improper access control mechanisms within the Windows Ancillary Function Driver for WinSock. Attackers with local access can exploit this flaw to gain elevated privileges without requiring user interaction. The attack complexity is considered low, as it does not require advanced skills.
The potential impact includes high confidentiality, integrity, and availability risks, making it critical for organizations to monitor their systems for unauthorized access attempts. Affected systems may suffer from unauthorized modifications and data breaches if left unpatched.
Risk & Impact Analysis
Risk to organizations includes potential unauthorized access to sensitive data and system resources, leading to significant operational disruptions and data loss. The urgency of addressing this vulnerability is high, given its CVSS score and local attack vector, underscoring the need for immediate action.
With an exploitation potential outlined by its high CVSS score, organizations should assess their environments for affected systems and apply necessary patches as soon as possible to mitigate the risks associated with this vulnerability.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
Affected versions include multiple releases of Windows 10 (1607, 1809, 21h2, 22h2) and Windows 11 (23h2, 24h2, 25h2), as well as various Windows Server editions. All versions prior to vendor patch are susceptible to this vulnerability.
Mitigation & Remediation
Organizations should ensure that they apply the latest patches from Microsoft to remediate this vulnerability effectively. For those unable to patch immediately, implementing additional access controls and monitoring for suspicious local access attempts can help mitigate risks until patches are applied. For further guidance, organizations may consider professional services such as penetration testing to identify and address potential vulnerabilities in their systems.
Detection Guidance
Monitoring logs for unauthorized access attempts and behavioral anomalies can help detect exploitation attempts related to this vulnerability. Organizations should look for any unusual privilege escalation activities and ensure proper logging is in place to capture relevant events.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2026-21238 highlights the importance of access control mechanisms in software design. This vulnerability represents a trend where local elevation of privilege vulnerabilities can lead to severe security incidents, especially in environments with sensitive data.
Security teams should continuously evaluate their systems for vulnerabilities and prioritize regular updates and patches as part of their cybersecurity strategy. For more information on vulnerability management best practices, refer to our vulnerability management program guide.
Additionally, engaging in regular security assessments and adopting a proactive security posture can help organizations stay ahead of potential threats. For strategic insights on penetration testing methodologies, check out our penetration testing methodology article.
Finally, understanding the evolving threat landscape is crucial. For insights on recent trends in ransomware targeting, see our 2026 ransomware targeting trends report.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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