CVE-2020-1206 — Windows SMBv3 Client/Server Information Disclosure Vulnerability

Executive Summary

An information disclosure vulnerability exists in the way that the Microsoft Server Message Block 3.1.1 (SMBv3) protocol handles certain requests. An attacker who successfully exploited the vulnerability could obtain information to further compromise the user’s system. To exploit the vulnerability against a server, an unauthenticated attacker could send a specially crafted packet to a targeted SMBv3 server. To exploit the vulnerability against a client, an unauthenticated attacker would need to configure a malicious SMBv3 server and convince a user to connect to it. The security update addresses the vulnerability by correcting how the SMBv3 protocol handles these specially crafted requests.

Overview

7.5

CVSS HIGH

Important

MS Severity

Not Exploited

MS Exploit Status

More Likely

MS Exploit Likelihood

Category Information Disclosure

Released Jun 9 2020

Last Updated Jun 9 2020

Publicly Disclosed No

CISA KEV Not Listed

Known Exploits None Known

EPSS Score 0.09463 — 0.94984 percentile

NVD CVSS 7.5 HIGH — differs from MSRC

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:P/RL:O/RC:C

ATTACK VECTOR

Network

ATTACK COMPLEXITY

Low

PRIVILEGES REQUIRED

None

USER INTERACTION

None

SCOPE

Unchanged

CONFIDENTIALITY

High

INTEGRITY

None

AVAILABILITY

None

EXPLOIT CODE MATURITY

Proof-of-Concept

REMEDIATION LEVEL

Official Fix

REPORT CONFIDENCE

Confirmed

Temporal Score: 7.7

EPSS Score

0.09463

probability of exploitation in the next 30 days

0.94984 percentile - updated 2026-08-14

View on FIRST.org

Affected Products

12 affected products

Product	KB Article	Severity	Impact	Restart Required
Windows 10 Version 1903 for 32-bit Systems	`4560960 (Security Update)`	Important	Information Disclosure	Yes
Windows 10 Version 1903 for ARM64-based Systems	`4560960 (Security Update)`	Important	Information Disclosure	Yes
Windows 10 Version 1903 for x64-based Systems	`4560960 (Security Update)`	Important	Information Disclosure	Yes
Windows 10 Version 1909 for 32-bit Systems	`4560960 (Security Update)`	Important	Information Disclosure	Yes
Windows 10 Version 1909 for ARM64-based Systems	`4560960 (Security Update)`	Important	Information Disclosure	Yes
Windows 10 Version 1909 for x64-based Systems	`4560960 (Security Update)`	Important	Information Disclosure	Yes
Windows 10 Version 2004 for 32-bit Systems	`4557957 (Security Update)`	Important	Information Disclosure	Yes
Windows 10 Version 2004 for ARM64-based Systems	`4557957 (Security Update)`	Important	Information Disclosure	Yes
Windows 10 Version 2004 for x64-based Systems	`4557957 (Security Update)`	Important	Information Disclosure	Yes
Windows Server, version 1903 (Server Core installation)	`4560960 (Security Update)`	Important	Information Disclosure	Yes
Windows Server, version 1909 (Server Core installation)	`4560960 (Security Update)`	Important	Information Disclosure	Yes
Windows Server, version 2004 (Server Core installation)	`4557957 (Security Update)`	Important	Information Disclosure	Yes

Patches

2 patches

Article	Type	Restart
`4560960`	Security Update	Yes
`4557957`	Security Update	Yes

Exploits & PoC

4 public PoCs

Unverified third-party code

Public proof-of-concept repositories aggregated from PoC-in-GitHub. They are not reviewed and may be incomplete, non-functional, or malicious — inspect the code before running anything.

Repository	Stars	Published	Description
jamf/CVE-2020-1206-POC	144	2020-04-05	CVE-2020-1206 Uninitialized Kernel Memory Read POC
Info-Security-Solution-Kolkata/CVE-2020-1206-Exploit	0	2020-07-04
Info-Security-Solution-Kolkata/Smbleed-CVE-2020-1206-Exploit	0	2020-07-04
datntsec/CVE-2020-1206	0	2021-01-07

Detection Rules

No public Sigma or Nuclei detection rule has been mapped to this CVE yet. Coverage is concentrated on exploited / high-profile vulnerabilities; check SigmaHQ for updates.

Acknowledgments

Michael Maltsev of ZecOps

References

MSRC Advisory MITRE NVD