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Fencer Vulns
critical 9.8

CVE-2018-8421 in the critical feed json

A remote code execution vulnerability exists when Microsoft .NET Framework processes untrusted input, aka ".NET Framework Remote Code Execu…

published 2018-09-13 8 y ago modified 2026-06-17 4 mo ago also EUVD-2018-20057

cvss
9.8
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
29.1%
EPSS 29.1% chance of exploitation in 30 days, percentile 98%
public exploits
0
none known

Summary

A remote code execution vulnerability exists when Microsoft .NET Framework processes untrusted input, aka ".NET Framework Remote Code Execution Vulnerability." This affects Microsoft .NET Framework 4.6, Microsoft .NET Framework 3.5, Microsoft .NET Framework 4.7/4.7.1/4.7.2, Microsoft .NET Framework 3.0, Microsoft .NET Framework 3.5.1, Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2, Microsoft .NET Framework 4.5.2, Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.1/4.7.2, Microsoft .NET Framework 4.7.1/4.7.2, Microsoft .NET Framework 4.7.2, Microsoft .NET Framework 2.0.

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-2018-8421 updated cvss 7.8

NET: RCE when processing untrusted input

  • Red Hat .NET Core 1.0 on Red Hat Enterprise Linux rh-dotnetcore10, rh-dotnetcore10-dotnetcore Red Hat .NET Core 1.1 on Red Hat Enterprise Linux rh-dotnetcore11, rh-dotnetcore11-dotnetcore Red Hat .NET Core 2.0 on Red Hat Enterprise Linux rh-dotnet20, rh-dotnet20-dotnet Red Hat .NET Core 2.1 on Red Hat Enterprise Linux rh-dotnet21, rh-dotnet21-dotnet, rh-dotnet21-runtime, rh-dotnet21-dotnet-host, rh-dotnet21-dotnet-sdk-2.1, rh-dotnet21-dotnet-runtime-2.1, +3 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

29.07% chance of exploitation in the next 30 days, higher than 98% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.0 9.8 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 10.0 AV:N/AC:L/Au:N/C:C/I:C/A:C

Affected products

  • Microsoft Microsoft .NET Framework

Classification

Weakness
  • CWE-20 Improper Input Validation

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.