Severity: High
A high-severity vulnerability has been disclosed affecting the Windows Ancillary Function Driver for WinSock (afd.sys) across supported versions of Windows desktop and server operating systems.
The vulnerability, tracked as CVE-2026-68820, is a use-after-free vulnerability in the Windows Ancillary Function Driver for WinSock (afd.sys). A flaw in the way this kernel-mode driver manages internal memory structures means that a locally authenticated attacker can manipulate memory that has already been freed, triggering a use-after-free condition. This allows an attacker with local access to escalate privileges on the affected host, potentially gaining elevated or SYSTEM-level access without requiring administrator rights. This class of vulnerability is commonly leveraged as a second-stage exploit in broader attack chains, combined with an initial access vector to achieve full system compromise.
As part of Beeks’ commitment to supporting operational resilience and cyber risk management, this advisory is intended to help organisations assess exposure and implement appropriate mitigations.
Affected software:
- Windows Ancillary Function Driver for WinSock (afd.sys) – affected Windows releases prior to the patched version
- Windows 10 (supported versions)
- Windows 11 (supported versions)
- Windows Server (supported versions)
Immediate Recommended Actions:
- Apply the latest security patches released by Microsoft to remediate this vulnerability — this is the primary and most effective remediation.
- Where immediate patching is not possible, restrict local interactive and remote access to affected systems to minimise the risk of exploitation by low-privileged users.
- Ensure endpoint detection and response (EDR) tooling is active and up to date on all affected hosts, as behavioural detections may identify exploitation attempts in the absence of a patch.
- Review and audit systems for indicators of unexpected privilege escalation events, particularly on hosts exposed to lower-privileged or untrusted user accounts.
- Monitor vendor security channels and threat intelligence feeds for further indicators of compromise and updated guidance as they become available.
Further Information:
For detailed information on the vulnerability, please refer to the following sources:
https://nvd.nist.gov/vuln/detail/CVE-2026-68820
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-68820
For detailed information on how to apply the security patch for this vulnerability, please refer to:
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-68820
If you have any questions or require further assistance, please contact [email protected] or reach out to your Beeks account representative.
This advisory is issued to help ensure the security of your systems and prevent unauthorised access to sensitive data. Beeks remains committed to providing timely security information and support to safeguard your infrastructure.
Beeks will continue to monitor this and related vulnerabilities and provide updates through our Security Advisory Feed.
