Home/CVE/.NET Core and Visual Studio Denial of Service Vulnerability
CVE

CVE-2021-26423

.NET Core and Visual Studio Denial of Service Vulnerability

.NET Core and Visual Studio Denial of Service Vulnerability.

HIGH · CVSS 7.5 EPSS 0.03366
Schedule remediation
  • CVSS base score ≥ 7.0
Sigma rules7 YARA rules0
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Affected Products & Versions

8
microsoft .net>= 5.0 and <= 5.0.8
microsoft .net core>= 2.1 and <= 2.1.28
microsoft .net core>= 3.1 and <= 3.1.17
microsoft powershell core>= 7.0 and < 7.0.7
microsoft powershell core>= 7.1 and < 7.1.4
microsoft visual studio 2017>= 15.0 and <= 15.9
microsoft visual studio 2019>= 16.0 and <= 16.10
microsoft visual studio 2019all versions
▤

Affected Packages

23
Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
NuGet Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.linux-arm64 HIGH fixed in 5.0.9
NuGet Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.linux-x64 HIGH fixed in 5.0.9
NuGet Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.osx-x64 HIGH fixed in 5.0.9
NuGet Microsoft.NETCore.App.Runtime.Mono.LLVM.linux-arm64 HIGH fixed in 5.0.9
NuGet Microsoft.NETCore.App.Runtime.Mono.LLVM.linux-x64 HIGH fixed in 5.0.9
NuGet Microsoft.NETCore.App.Runtime.Mono.LLVM.osx-x64 HIGH fixed in 5.0.9
NuGet Microsoft.NETCore.App.Runtime.Mono.linux-arm HIGH fixed in 5.0.9
NuGet Microsoft.NETCore.App.Runtime.Mono.linux-arm64 HIGH fixed in 5.0.9
NuGet Microsoft.NETCore.App.Runtime.Mono.linux-musl-x64 HIGH fixed in 5.0.9
NuGet Microsoft.NETCore.App.Runtime.Mono.linux-x64 HIGH fixed in 5.0.9
NuGet Microsoft.NETCore.App.Runtime.Mono.osx-x64 HIGH fixed in 5.0.9
NuGet Microsoft.NETCore.App.Runtime.linux-arm HIGH fixed in 3.1.18
NuGet Microsoft.NETCore.App.Runtime.linux-arm64 HIGH fixed in 3.1.18
NuGet Microsoft.NETCore.App.Runtime.linux-musl-arm HIGH fixed in 5.0.9
NuGet Microsoft.NETCore.App.Runtime.linux-musl-arm64 HIGH fixed in 3.1.18
NuGet Microsoft.NETCore.App.Runtime.linux-musl-x64 HIGH fixed in 3.1.18
NuGet Microsoft.NETCore.App.Runtime.linux-x64 HIGH fixed in 3.1.18
NuGet Microsoft.NETCore.App.Runtime.osx-x64 HIGH fixed in 3.1.18
NuGet Microsoft.NETCore.App.Runtime.rhel.6-x64 HIGH fixed in 3.1.18
NuGet Microsoft.NETCore.App.Runtime.win-arm HIGH fixed in 3.1.18
NuGet Microsoft.NETCore.App.Runtime.win-arm64 HIGH fixed in 3.1.18
NuGet Microsoft.NETCore.App.Runtime.win-x64 HIGH fixed in 3.1.18
NuGet Microsoft.NETCore.App.Runtime.win-x86 HIGH fixed in 3.1.18
◈

Sigma Hunt Rules

7
Exact rules name this CVE ID. Product rules name an affected product in their title. Related rules cover techniques used by actors who exploited this CVE. Showing the most relevant matches; the complete related set is on the full drill-down.
producthighUAC Bypass Using .NET Code Profiler on MMC
producthighPotential AMSI Bypass Via .NET Reflection
producthighETW Logging Tamper In .NET Processes Via CommandLine
producthighETW Logging Disabled In .NET Processes - Registry
producthighETW Logging Disabled In .NET Processes - Sysmon Registry
productmediumPowerShell Core DLL Loaded Via Office Application
▣

Scoring & Timeline

7.5
HIGH · CVSS v3.1 · secure@microsoft.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD12 Aug 2021 · 06:15 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
⚑

Vendor Advisories

5
msrcCVE-2021-26423Denial of Service
rhsaRHSA-2021:3142Low
rhsaRHSA-2021:3143Low
rhsaRHSA-2021:3148Low
rhsaRHSA-2021:3147Low
🔗

References & Sources

1
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26423PatchVendor Advisory
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