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Mallory
High

Remote Code Execution in Windows Deployment Services

IdentifiersCVE-2026-42987CWE-416· Use After Free

CVE-2026-42987 is a use-after-free vulnerability in Microsoft Windows Deployment Services (WDS), the Windows Server role used for network-based OS deployment. The flaw affects WDS handling of network traffic associated with deployment operations and is described as reachable over the network via TFTP-facing functionality. Available reporting indicates the bug can be triggered through specially crafted or malicious TFTP traffic and may involve a timing/race condition that leads WDS to access memory after it has been freed. An unauthenticated attacker can exploit this memory corruption condition against a Windows Server system running the WDS role to achieve remote code execution.

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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 allows unauthorized remote code execution on an affected Windows Server running Windows Deployment Services. Because WDS is a server-side deployment component, compromise could let an attacker hijack the deployment server, execute arbitrary code in the server context, disrupt provisioning operations, and potentially use the server as a foothold for further compromise of deployment infrastructure or adjacent enterprise systems.

Mitigation

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

If immediate patching is not possible, reduce exposure by disabling Windows Deployment Services where not required, restricting or filtering access to WDS and its TFTP service to only trusted deployment networks, isolating deployment infrastructure from general user and internet-reachable networks, and monitoring for anomalous or malformed TFTP traffic targeting WDS. No specific vendor mitigation beyond patching is provided in the supplied content.

Remediation

Patch, then assume compromise.

Apply Microsoft's June 2026 security update for CVE-2026-42987. Prioritize patching Windows Server systems with the Windows Deployment Services role installed, especially servers exposed to network paths from untrusted or less-trusted segments and those listening for TFTP traffic as part of PXE/deployment workflows. Standard remediation is to deploy the vendor fix across affected Windows Server 2012 through 2025 environments where WDS is in use.
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 Serveroperating_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 2025operating_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 signatures

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 activity1

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