Vulnerability report

Exploitation attempts observed in the wild Confirmed confidence In CISA KEV

CVE-2020-0638

Windows

Microsoft / Windows · 10 Version 1709 for 32-bit Systems

Watch CVE-2020-0638 Browse KEV feed
Severity
CVSS 7.8 · High
Confidence
Confirmed
Exploit status
Exploitation attempts observed in the wild
EPSS
2.4%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2020-0638 is a vulnerability affecting Microsoft Windows and 11 other products. An elevation of privilege vulnerability exists in the way the Update Notification Manager handles files.To exploit this...

Have exploitation attempts been observed?

Yes. Exploitation attempts have been reported for this vulnerability. Previdian lists it as a known exploited vulnerability. Listed in CISA KEV. Also reported by third-party sources. Confidence is confirmed.

Who is affected?

Microsoft / Windows 10 version 1709 for 32-bit systems.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

Windows

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'.

Microsoft Affected
Windows
10 Version 1709 for 32-bit Systems 10 Version 1803 for 32-bit Systems 10 Version 1809 for ARM64-based Systems 10 Version 1803 for x64-based Systems 10 Version 1709 for ARM64-based Systems 10 Version 1709 for x64-based Systems 10 Version 1803 for ARM64-based Systems 10 Version 1809 for 32-bit Systems 10 Version 1809 for x64-based Systems
Microsoft Affected
Windows 10 Version 1903 for ARM64-based Systems
unspecified
Microsoft Affected
Windows 10 Version 1903 for 32-bit Systems
unspecified
Microsoft Affected
Windows 10 Version 1903 for x64-based Systems
unspecified
Microsoft Affected
Windows Server
2019 2019 (Core installation) version 1803 (Core Installation)
Microsoft Affected
Windows Server, version 1903 (Server Core installation)
unspecified
Microsoft Affected
Windows 10 Version 1909 for 32-bit Systems
unspecified
Microsoft Affected
Windows 10 Version 1909 for x64-based Systems
unspecified
Microsoft Affected
Windows Server, version 1909 (Server Core installation)
unspecified
Microsoft Affected
Windows 10 Version 1909 for ARM64-based Systems
unspecified
Published
14 Jan 2020
Exploitation Attempts Reported
23 May 2022
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None

Tags

windows ransomware cisa malware microsoft

CVE References

Exploitation evidence

Evidence of exploitation attempts

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploitation attempts observed in the wild

CISA

Recorded 23 May 2022

A trusted third party reported exploitation attempts.

Targeted by malware-related exploitation attempts

CISA

Recorded 23 May 2022

Exploitation attempts against this vulnerability are associated with malware-related payloads.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

Learn about Pro API access
Source Added
CISA First 2022-05-23 00:00 UTC
CVE 2026-08-12 04:21 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts
0
0
0

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Scanner coverage

No scanner integrations recorded yet.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

No detection artifacts or sensor request patterns are available for this CVE yet.

Check back as sensor telemetry and scanner integrations are updated.

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

7.8 High

Potential damage if exploited. Separate from whether attackers are using it.

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS

2.4%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Improper Link Resolution Before File Access ('Link Following') CWE-59

All CVSS Scores

CVSS v3.1 7.8 High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v2.0 4.6 Medium

AV:L/AC:L/Au:N/C:P/I:P/A:P

Timeline

From disclosure to observed exploitation attempts

  1. 04:21 UTC

    KEV confirmed by CVE

    Exploitation attempts reported by an external source

  2. 00:00 UTC

    Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  3. 00:00 UTC

    Targeted by malware-related exploitation attempts

    Malware-related exploitation attempts or payloads reported

  4. 23:11 UTC

    CVE published

    Vulnerability disclosed publicly

  5. 00:00 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2020-0638

Sample API response 
{
  "cve_id": "CVE-2020-0638",
  "confidence": "Confirmed",
  "cvss_score": 7.8,
  "cvss_estimated": false,
  "epss_score": 0.0237,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}