Known exploited · Microsoft
CVE-2020-1147: Microsoft .NET Framework, SharePoint, and Visual Studio Remote Code Execution Vulnerability
What it is
Microsoft .NET Framework, Microsoft SharePoint, and Visual Studio contain a remote code execution vulnerability when the software fails to check the source markup of XML file input. Successful exploitation allows an attacker to execute code in the context of the process responsible for deserialization of the XML content.
- Vendor
- Microsoft
- Product
- .NET Framework, SharePoint, Visual Studio
- Added to KEV
- November 3, 2021
- CISA due date
- May 3, 2022
- Ransomware use
- Unknown
- Weakness
- Not mapped by CISA
What CISA requires
Apply updates per vendor instructions.
Forensic triage
No
What to do now
- Find every instance of .NET Framework, SharePoint, Visual Studio you run, including the forgotten ones, and check its version against the vendor advisory.
- Apply the vendor's fix or mitigation, before May 3, 2022 if you are bound by CISA's deadline, sooner if it faces the internet.
- Assume it was tried against you already: look for signs of exploitation from the date it was added, not from the day you patched.
References
H2 Security
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Start freeSource: CISA Known Exploited Vulnerabilities Catalog (public domain), catalog version 2026.10.01.