Skip to main content
Live Webinar with SANS (June 25)— Agentic CTI Automation for Fun & ProfitRegister Free
Mallory
High

Windows Ancillary Function Driver for WinSock Type Confusion Elevation of Privilege

IdentifiersCVE-2026-20860CWE-843· Access of Resource Using…

CVE-2026-20860 is an elevation-of-privilege vulnerability in the Windows Ancillary Function Driver for WinSock (AFD.sys). The flaw is described as an access of resource using an incompatible type, i.e., a type confusion condition, in the AFD component. Successful exploitation allows a locally authorized attacker to trigger the vulnerable kernel-mode code path and elevate privileges on the affected Windows system. Microsoft and supporting reporting classify this as a local privilege escalation issue with CVSS 7.8, and public reporting notes it was considered 'Exploitation More Likely' at release. The available content does not provide the specific vulnerable function or code path beyond identifying the affected component and the type confusion class.

Share:
For your environment

Are you exposed to this one?

Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.

ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation results in local elevation of privilege. An attacker with an existing local foothold and authorization on the target system could escalate privileges, potentially to SYSTEM, gaining control over the affected host beyond the permissions of the original account. As a kernel-adjacent Windows component issue, this can enable follow-on actions such as disabling protections, accessing restricted resources, establishing persistence, or using the host for further lateral movement. The provided content does not include evidence of in-the-wild exploitation for this specific CVE at release.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, reduce exposure by limiting opportunities for local code execution and privilege-escalation chaining: restrict interactive logon to trusted users, minimize the presence of untrusted code on endpoints, enforce application control, and monitor for suspicious local privilege-escalation behavior involving AFD/WinSock-related activity. Because this is a local authorized attacker scenario, hardening endpoint access and preventing initial compromise are the primary interim mitigations. The supplied content does not provide any vendor-specific workaround.

Remediation

Patch, then assume compromise.

Apply Microsoft's January 2026 security update that addresses CVE-2026-20860 in the Windows Ancillary Function Driver for WinSock. Standard remediation is to deploy the relevant cumulative Windows security updates to all affected systems and verify successful installation through normal patch validation processes. No more specific vendor remediation details are provided in the supplied content.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
Microsoft CorporationWindows 10 1607operating_system
Microsoft CorporationWindows 10 1809operating_system
Microsoft CorporationWindows 10 21h2operating_system
Microsoft CorporationWindows 10 22h2operating_system
Microsoft CorporationWindows 11 23h2operating_system
Microsoft CorporationWindows 11 24h2operating_system
Microsoft CorporationWindows 11 25h2operating_system
Microsoft CorporationWindows Server 2008operating_system
Microsoft CorporationWindows Server 2008 R2operating_system
Microsoft CorporationWindows Server 2008 Sp2operating_system
Microsoft CorporationWindows Server 2012operating_system
Microsoft CorporationWindows Server 2012 R2operating_system
Microsoft CorporationWindows Server 2016operating_system
Microsoft CorporationWindows Server 2019operating_system
Microsoft CorporationWindows Server 2022operating_system
Microsoft CorporationWindows Server 2022 23h2operating_system
Microsoft CorporationWindows Server 2025operating_system
Microsoft CorporationWindows Server 23h2operating_system

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.
Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures1

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity2

Community discussion across Reddit, Mastodon, and other social sources.