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

CVE-2021-1721

.NET Core and Visual Studio Denial of Service Vulnerability

.NET Core and Visual Studio Denial of Service Vulnerability.

MEDIUM · CVSS 6.5 EPSS 0.09338
Monitor
  • EPSS percentile: top 7% of all CVEs by exploitation likelihood
Sigma rules7 YARA rules0
▤

Affected Products & Versions

6
microsoft .net>= 5.0 and <= 5.0.2
microsoft .net core>= 2.1 and <= 2.1.24
microsoft .net core>= 3.1 and <= 3.1.11
microsoft powershell coreall versions
microsoft visual studio 2017>= 15.0 and <= 15.9
microsoft visual studio 2019>= 16.0 and <= 16.8
▤

Affected Packages

36
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 MODERATE fixed in 2.1.25
NuGet Microsoft.NETCore.App.Host.linux-arm MODERATE fixed in 3.1.12
NuGet Microsoft.NETCore.App.Host.linux-arm64 MODERATE fixed in 3.1.12
NuGet Microsoft.NETCore.App.Host.linux-musl-arm64 MODERATE fixed in 3.1.12
NuGet Microsoft.NETCore.App.Host.linux-musl-x64 MODERATE fixed in 3.1.12
NuGet Microsoft.NETCore.App.Host.linux-x64 MODERATE fixed in 3.1.12
NuGet Microsoft.NETCore.App.Host.osx-x64 MODERATE fixed in 3.1.12
NuGet Microsoft.NETCore.App.Host.rhel.6-x64 MODERATE fixed in 3.1.12
NuGet Microsoft.NETCore.App.Host.win-arm MODERATE fixed in 3.1.12
NuGet Microsoft.NETCore.App.Host.win-arm64 MODERATE fixed in 3.1.12
NuGet Microsoft.NETCore.App.Host.win-x64 MODERATE fixed in 3.1.12
NuGet Microsoft.NETCore.App.Host.win-x86 MODERATE fixed in 3.1.12
NuGet Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.linux-arm64 MODERATE fixed in 5.0.3
NuGet Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.linux-x64 MODERATE fixed in 5.0.3
NuGet Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.osx-x64 MODERATE fixed in 5.0.3
NuGet Microsoft.NETCore.App.Runtime.Mono.LLVM.linux-arm64 MODERATE fixed in 5.0.3
NuGet Microsoft.NETCore.App.Runtime.Mono.LLVM.linux-x64 MODERATE fixed in 5.0.3
NuGet Microsoft.NETCore.App.Runtime.Mono.LLVM.osx-x64 MODERATE fixed in 5.0.3
NuGet Microsoft.NETCore.App.Runtime.Mono.linux-arm MODERATE fixed in 5.0.3
NuGet Microsoft.NETCore.App.Runtime.Mono.linux-arm64 MODERATE fixed in 5.0.3
NuGet Microsoft.NETCore.App.Runtime.Mono.linux-musl-x64 MODERATE fixed in 5.0.3
NuGet Microsoft.NETCore.App.Runtime.Mono.linux-x64 MODERATE fixed in 5.0.3
NuGet Microsoft.NETCore.App.Runtime.Mono.osx-x64 MODERATE fixed in 5.0.3
NuGet Microsoft.NETCore.App.Runtime.android-arm MODERATE fixed in 5.0.3
NuGet Microsoft.NETCore.App.Runtime.android-arm64 MODERATE fixed in 5.0.3
NuGet Microsoft.NETCore.App.Runtime.android-x64 MODERATE fixed in 5.0.3
NuGet Microsoft.NETCore.App.Runtime.android-x86 MODERATE fixed in 5.0.3
NuGet Microsoft.NETCore.App.Runtime.browser-wasm MODERATE fixed in 5.0.3
NuGet Microsoft.NETCore.App.Runtime.ios-arm MODERATE fixed in 5.0.3
NuGet Microsoft.NETCore.App.Runtime.ios-x64 MODERATE fixed in 5.0.3
NuGet Microsoft.NETCore.App.Runtime.ios-x86 MODERATE fixed in 5.0.3
NuGet Microsoft.NETCore.App.Runtime.linux-arm MODERATE fixed in 3.1.12
NuGet Microsoft.NETCore.App.Runtime.linux-arm64 MODERATE fixed in 3.1.12
NuGet Microsoft.NETCore.App.Runtime.linux-musl-arm MODERATE fixed in 5.0.3
NuGet Microsoft.NETCore.App.Runtime.linux-musl-arm64 MODERATE fixed in 3.1.12
NuGet Microsoft.NETCore.App.Runtime.linux-musl-x64 MODERATE fixed in 3.1.12
◈

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.
productmediumPowerShell Core DLL Loaded Via Office Application
productmediumPowerShell Core DLL Loaded By Non PowerShell Process
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
▣

Scoring & Timeline

6.5
MEDIUM · 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 NVD25 Feb 2021 · 11:15 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
⚑

Vendor Advisories

7
msrcCVE-2021-1721Denial of Service
rhsaRHSA-2021:0472Important
rhsaRHSA-2021:0473Important
rhsaRHSA-2021:0470Important
rhsaRHSA-2021:0471Important
🔗

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-2021-1721PatchVendor Advisory
Intelligence Graph · click any node to traverse
CVETechnique ActorTool Family
drag to reposition · click any node to traverse · button top-right enlarges
External lookups - second-class, for what we don’t hold ourselves
NVDCVE.orgCISAVulnersExploit-DBGitHub PoCVulnCheck KEVGreyNoise
Vulnerabilities
CISA KEV catalog
CWE weaknesses
CAPEC attack patterns
Package vulnerabilities
Threat intelligence
Threat actors
Tools & malware
ATT&CK techniques
IOCs
Detection & defense
Sigma rules
YARA rules
Atomic Red Team tests
D3FEND countermeasures
Compliance
NIST 800-53
ISO 27001:2022
SOC 2 TSC
PCI-DSS v4.0
CIS Controls v8.1
About
All capabilities
Live statistics
Data sources
Privacy policy
Terms of service
threatengine.sh  ·  Open-source threat intelligence platform  ·  100+ authoritative sources  ·  Every fact traces to its origin