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Mallory
High

Out-of-bounds read information disclosure in Windows RDP

IdentifiersCVE-2026-45639CWE-125· Out-of-bounds Read

CVE-2026-45639 is an information disclosure vulnerability in the Windows Remote Desktop Protocol (RDP) stack caused by an out-of-bounds read. A remote, unauthenticated attacker can send crafted RDP traffic to a vulnerable system and trigger the service to return data from adjacent memory regions. According to the provided context, successful exploitation can expose portions of process memory, including potentially credentials, session tokens, or protocol state data. Microsoft addressed the issue in its June 9, 2026 security updates.

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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 to disclose sensitive information from process memory over the network. The confidentiality impact is high, while integrity and availability impact are not indicated. Exposed memory may include credentials, session tokens, protocol state data, or other sensitive in-memory material. The vulnerability may also be useful as part of a broader exploit chain by providing information that supports follow-on attacks.

Mitigation

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

If patching cannot be completed immediately, reduce exposure by limiting RDP access to trusted networks, placing RDP behind VPNs or bastion hosts, enforcing strong authentication, and monitoring for unusual RDP connection patterns. Prioritize internet-exposed RDP systems for remediation.

Remediation

Patch, then assume compromise.

Apply the Microsoft security update for CVE-2026-45639 released as part of the June 9, 2026 security updates/Patch Tuesday rollout. Deploy the relevant cumulative update or rollup package for all affected Windows client, server, and Remote Desktop client/Windows App client for Windows Desktop installations identified in the environment.
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 Desktopapplication
Microsoft CorporationWindowsoperating_system
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 11 26h1operating_system
Microsoft CorporationWindows App Client For Windows Desktopapplication
Microsoft CorporationWindows Rdpoperating_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 activity

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