Windows Remote Desktop Services Elevation of Privilege Vulnerability
CVE-2026-40398 is a heap-based buffer overflow in Windows Remote Desktop Services / Windows Remote Desktop that allows an authorized attacker to elevate privileges locally. The available content indicates the flaw is triggered after authentication by a low-privileged user and results in privilege escalation to SYSTEM. Specific vulnerable routines or code paths are not provided in the supplied material.
Are you exposed to this one?
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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.
Mitigation
If you can’t patch tonight, do this now.
Remediation
Patch, then assume compromise.
Exploits
No public exploits tracked yet. Mallory keeps watching.
No public exploit code observed for this vulnerability.
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.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
3 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
An elevation of privilege vulnerability in Windows Remote Desktop Services.
A buffer overflow elevation-of-privilege vulnerability in Windows Remote Desktop Services that allows an authenticated low-privilege attacker to escalate to SYSTEM.
An important Windows Remote Desktop Services elevation of privilege vulnerability that Microsoft determined is more likely to be exploited.
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.