What’s Vulnerable › Vulnerabilities

CVE-2020-1112: Windows Background Intelligent Transfer Service Elevation of Privilege Vulnerability

• Severity: high (CVSS 8.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 3.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-05-21 · updated 2026-08-19
• Weakness: CWE-434

Description

An elevation of privilege vulnerability exists when the Windows Background Intelligent Transfer Service (BITS) IIS module improperly handles uploaded content. An attacker who successfully exploited this vulnerability could upload restricted file types to an IIS-hosted folder. To exploit this vulnerability, an attacker would require permissions to upload files via BITS. An attacker could then submit a specially crafted request to upload a file. The security update addresses the vulnerability by correcting how Windows BITS validates file names.

Affected products

• Microsoft Windows 10 Version 1607: 1607, 1709, 1803, 1809, 1903, 1909
• Microsoft Windows 7: all versions
• Microsoft Windows 8.1: all versions
• Microsoft Windows RT 8.1: all versions
• Microsoft Windows Server 2008: r2-sp1
• Microsoft Windows Server 2012: r2
• Microsoft Windows Server 2016: all versions
• Microsoft Windows Server 2019: all versions
• Microsoft Windows 10 Version 1507: from 10.0.10240.0 before publication — fixed in publication
• Microsoft Windows 10 1607: from 10.0.14393.0 before publication — fixed in publication
• Microsoft Windows 10 1709: from 10.0.0 before publication — fixed in publication
• Microsoft Windows 10 Version 1709 for 32-bit Systems: from 10.0.0 before publication — fixed in publication
• Microsoft Windows 10 1803: from 10.0.0 before publication — fixed in publication
• Microsoft Windows 10: from 10.0.17763.0 before publication — fixed in publication
• Microsoft Windows 10 Version 1903 for 32-bit Systems: from 10.0.0 before publication — fixed in publication
• Microsoft Windows 10 Version 1903 for ARM64-based Systems: from 10.0.0 before publication — fixed in publication
• Microsoft Windows 10 Version 1903 for x64-based Systems: from 10.0.0 before publication — fixed in publication
• Microsoft Windows 10 1909: from 10.0.0 before publication — fixed in publication
• Microsoft Windows 7: from 6.1.0 before publication — fixed in publication
• Microsoft Windows 7 Service Pack 1: from 6.1.0 before publication — fixed in publication
• Microsoft Windows 8.1: from 6.3.0 before publication — fixed in publication
• Microsoft Windows Server 2008 R2 Service Pack 1: from 6.1.7601.0 before publication — fixed in publication
• Microsoft Windows Server 2008 Service Pack 2: from 6.0.6003.0 before publication — fixed in publication
• Microsoft Windows Server 2012: from 6.2.9200.0 before publication — fixed in publication
• Microsoft Windows Server 2012 R2: from 6.3.9600.0 before publication — fixed in publication
• Microsoft Windows Server 2016: from 10.0.14393.0 before publication — fixed in publication
• Microsoft Windows Server 2019: from 10.0.17763.0 before publication — fixed in publication
• Microsoft Windows Server, version 1803 (Server Core Installation): from 10.0.0 before publication — fixed in publication
• Microsoft Windows Server, version 1903 (Server Core installation): from 10.0.0 before publication — fixed in publication
• Microsoft Windows Server, version 1909 (Server Core installation): from 10.0.0 before publication — fixed in publication

How to fix

Upgrade to a fixed version: Microsoft Windows 10 Version 1507 publication; Microsoft Windows 10 1607 publication; Microsoft Windows 10 1709 publication; Microsoft Windows 10 Version 1709 for 32-bit Systems publication; Microsoft Windows 10 1803 publication; Microsoft Windows 10 publication; Microsoft Windows 10 Version 1903 for 32-bit Systems publication; Microsoft Windows 10 Version 1903 for ARM64-based Systems publication; Microsoft Windows 10 Version 1903 for x64-based Systems publication; Microsoft Windows 10 1909 publication; Microsoft Windows 7 publication; Microsoft Windows 7 Service Pack 1 publication. Check the vendor advisory for mitigations.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2020-1112
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1112

Get alerted when CVE-2020-1112 or the next vulnerability affects your stack