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Fencer Vulns
high 7.8

CVE-2020-1066 json

.NET Framework Elevation of Privilege Vulnerability

published 2020-05-21 6 y ago modified 2026-08-19 2 mo ago also EUVD-2020-11957

cvss
7.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.5%
EPSS 2.5% chance of exploitation in 30 days, percentile 84%
public exploits
0
none known

Summary

An elevation of privilege vulnerability exists in .NET Framework which could allow an attacker to elevate their privilege level. To exploit the vulnerability, an attacker would first have to access the local machine, and then run a malicious program. The update addresses the vulnerability by correcting how .NET Framework activates COM objects.

Patch / fix

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-1066 updated cvss 7.8

NET: local elevation of privilege

  • Red Hat .NET Core 2.1 on Red Hat Enterprise Linux rh-dotnet21-dotnet, rh-dotnet21-dotnet-host, rh-dotnet21-dotnet-sdk-2.1, rh-dotnet21-dotnet-runtime-2.1, rh-dotnet21-dotnet-sdk-2.1.3xx, rh-dotnet21-dotnet-sdk-2.1.4xx, +1 more Red Hat .NET Core 3.1 on Red Hat Enterprise Linux rh-dotnet31-dotnet, rh-dotnet31-dotnet-host, rh-dotnet31-dotnet-sdk-3.1, rh-dotnet31-dotnet-hostfxr-3.1, rh-dotnet31-dotnet-runtime-3.1, rh-dotnet31-dotnet-templates-3.1, +6 more Red Hat Enterprise Linux 8 dotnet, dotnet31, dotnet-host, dotnet-sdk-2.1, dotnet-runtime-2.1, dotnet-sdk-2.1.5xx, +1 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

2.52% chance of exploitation in the next 30 days, higher than 84% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 4.6 AV:L/AC:L/Au:N/C:P/I:P/A:P

Affected products

  • Microsoft Microsoft .NET Framework 3.0 Service Pack 2
  • Microsoft Microsoft .NET Framework 3.5.1

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.