CVE-2020-0609Public exploitNetwork attack vector

Unauthenticated code execution via fragmented UDP requests

Published Jan 14, 2020 · Updated Aug 4, 2024

Remote code execution in Microsoft Windows Server 2012, 2012 R2, 2016, and 2019 allows remote attackers to execute code as SYSTEM via RD Gateway. The UDP transport fragmentation handler accepts an unchecked fragment index and writes attacker-controlled data beyond the intended heap buffer. No authentication or user interaction is required, but RD Gateway must be installed and reachable over UDP, normally on port 3391.

CVSS severity9.8
Critical
EPSS probability74.90%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Remote code execution in Microsoft Windows Server 2012, 2012 R2, 2016, and 2019 allows remote attackers to execute code as SYSTEM via RD Gateway. The UDP transport fragmentation handler accepts an unchecked fragment index and writes attacker-controlled data beyond the intended heap buffer. No authentication or user interaction is required, but RD Gateway must be installed and reachable over UDP, normally on port 3391.

The record

CVE
CVE-2020-0609
Published
Jan 14, 2020
Updated
Aug 4, 2024
Vendor
Microsoft
Product
Windows Server
Classifications
CWE-787, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 14, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2012
  2. Affected versionversion=2012 R2
  3. Affected versionversion=2016
  4. Affected versionversion=2019

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Windows Serverversion=2012; version=2012 R2; version=2016; version=2019

Published CVSS scores

10.0NIST NVDAV:N/AC:L/Au:N/C:C/I:C/A:C
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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