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Mallory
High

Remote Desktop Client Remote Code Execution Vulnerability

IdentifiersCVE-2026-42985CWE-416· Use After Free

CVE-2026-42985 is a critical remote code execution vulnerability in Microsoft Remote Desktop Client. The flaw is described in the provided content as a heap-based buffer overflow / memory corruption issue, and Microsoft also mapped it to CWE-416 (use-after-free). Exploitation is possible over the network when a victim using a vulnerable Remote Desktop Client connects to an attacker-controlled or rogue Remote Desktop server. The malicious server can present malformed data, including a malformed security certificate as noted in the supporting contexts, to trigger the memory corruption condition in the client and achieve code execution on the victim system. Microsoft assigned CVSS v3.1 8.8 and assessed exploitation as more likely.

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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 an unauthorized attacker who controls a Remote Desktop Server to execute arbitrary code on the victim machine in the context of the Remote Desktop Client when the victim initiates a connection. The CVSS metrics in the provided content indicate high confidentiality, integrity, and availability impact, meaning compromise could result in full code execution with the ability to access data, modify system state, and disrupt system operation on the affected endpoint.

Mitigation

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

No specific vendor mitigation is provided in the supplied content beyond installing the official fix. As an interim risk-reduction measure, restrict or avoid outbound RDP connections from vulnerable clients to untrusted or attacker-controlled Remote Desktop servers, and limit user ability to initiate RDP sessions to non-approved hosts until patching is complete.

Remediation

Patch, then assume compromise.

Apply Microsoft's June 2026 security update for CVE-2026-42985 to all affected Remote Desktop Client installations. Prioritize patching endpoints used for remote work or that routinely initiate RDP connections to untrusted, external, partner, lab, or otherwise non-fully-trusted servers, as Microsoft assessed this vulnerability as exploitation more likely.
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 CorporationRemote Desktop Clientapplication

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.