Cyber Resilience

CVE-2020-0638

HighCISA KEVActive ExploitationEUVD ExploitedRansomware-linked

Published: 14 January 2020

Published
14 January 2020
Modified
29 October 2025
KEV Added
23 May 2022
Patch
CVSS Score v3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0148 81.4th percentile
Risk Priority 36 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2020-0638 is a high-severity Link Following (CWE-59) vulnerability in Microsoft Windows 10 1809. Its CVSS base score is 7.8 (High).

Operationally, ranked in the top 18.6% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.

The strongest mitigations our analysis identified are NIST 800-53 AC-3 (Access Enforcement) and AC-6 (Least Privilege).

Deeper analysis

CVE-2020-0638 is an elevation of privilege vulnerability in the Update Notification Manager component, arising from improper handling of files. The flaw is tracked under CWE-59 and carries a CVSS 3.1 base score of 7.8 reflecting local attack vector, low attack complexity, and low privileges required.

An attacker who has already obtained code execution on a target system can leverage the vulnerability to elevate privileges, resulting in full control over confidentiality, integrity, and availability of the affected system.

Microsoft has published an advisory detailing the issue, and the vulnerability appears in CISA's catalog of known exploited vulnerabilities, confirming observed in-the-wild exploitation.

EU & UK References

Vulnerability details

An elevation of privilege vulnerability exists in the way the Update Notification Manager handles files.To exploit this vulnerability, an attacker would first have to gain execution on the victim system, aka 'Update Notification Manager Elevation of Privilege Vulnerability'.

CWE(s)
KEV Date Added
23 May 2022

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

microsoft
windows 10 1709
all versions
microsoft
windows 10 1803
all versions
microsoft
windows 10 1809
all versions
microsoft
windows 10 1903
all versions
microsoft
windows 10 1909
all versions
microsoft
windows server 1803
all versions
microsoft
windows server 1903
all versions
microsoft
windows server 1909
all versions
microsoft
windows server 2019
all versions

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

prevent

Least privilege directly limits the ability of an attacker with initial code execution to escalate via the flawed Update Notification Manager file handling.

prevent

Access enforcement would block unauthorized file operations that the vulnerability uses to elevate privileges after initial execution.

prevent

Flaw remediation requires applying the vendor patch that eliminates the improper file-handling logic in the Update Notification Manager.

References