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TI-2020-01014 Aliases CVE-2020-1045GHSA-hxrm-9w7p-39cc

Microsoft ASP.NET Core Security Feature Bypass Vulnerability

Priority MEDIUM 48Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
None · High · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat.

Summary

<p>A security feature bypass vulnerability exists in the way Microsoft ASP.NET Core parses encoded cookie names.</p> <p>The ASP.NET Core cookie parser decodes entire cookie strings which could allow a malicious attacker to set a second cookie with the name being percent encoded.</p> <p>The security update addresses the vulnerability by fixing the way the ASP.NET Core cookie parser handles encoded names.</p>

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.05926 93rd percentileScored 2026-11-07
Fix Fixed ASP.NET Core 2.1 (Microsoft): publicationASP.NET Core 3.1 (Microsoft): publication+13 more productsRed Hat: 2 advisories

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
MicrosoftASP.NET Core 2.12.0 to before publicationpublicationPatch availableCNA
MicrosoftASP.NET Core 3.13.0 to before publicationpublicationPatch availableCNA
—Microsoft.AspNetCore.Http (NuGet)before 2.1.222.1.22Patch availableGHSA-hxrm-9w7p-39cc
—Microsoft.AspNetCore.App (NuGet)before 2.1.222.1.22Patch availableGHSA-hxrm-9w7p-39cc
—Microsoft.Owin (NuGet)before 4.1.14.1.1Patch availableGHSA-hxrm-9w7p-39cc
—Microsoft.AspNetCore.App.Runtime.linux-arm (NuGet)3.1.0 to before 3.1.83.1.8Patch availableGHSA-hxrm-9w7p-39cc
—Microsoft.AspNetCore.App.Runtime.linux-arm64 (NuGet)3.1.0 to before 3.1.83.1.8Patch availableGHSA-hxrm-9w7p-39cc
—Microsoft.AspNetCore.App.Runtime.linux-musl-x64 (NuGet)3.1.0 to before 3.1.83.1.8Patch availableGHSA-hxrm-9w7p-39cc
—Microsoft.AspNetCore.App.Runtime.linux-x64 (NuGet)3.1.0 to before 3.1.83.1.8Patch availableGHSA-hxrm-9w7p-39cc
—Microsoft.AspNetCore.App.Runtime.osx-x64 (NuGet)3.1.0 to before 3.1.83.1.8Patch availableGHSA-hxrm-9w7p-39cc
—Microsoft.AspNetCore.App.Runtime.win-arm (NuGet)3.1.0 to before 3.1.83.1.8Patch availableGHSA-hxrm-9w7p-39cc
—Microsoft.AspNetCore.App.Runtime.win-x64 (NuGet)3.1.0 to before 3.1.83.1.8Patch availableGHSA-hxrm-9w7p-39cc
—Microsoft.AspNetCore.App.Runtime.win-x86 (NuGet)3.1.0 to before 3.1.83.1.8Patch availableGHSA-hxrm-9w7p-39cc
—Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 (NuGet)3.1.0 to before 3.1.83.1.8Patch availableGHSA-hxrm-9w7p-39cc
—Microsoft.AspNetCore.App.Runtime.win-arm64 (NuGet)3.1.5 to before 3.1.83.1.8Patch availableGHSA-hxrm-9w7p-39cc
  • ASP.NET Core 2.1 VendorMicrosoft Affected 2.0 to before publication Fixed in publication Patch available CNA
  • ASP.NET Core 3.1 VendorMicrosoft Affected 3.0 to before publication Fixed in publication Patch available CNA
  • Microsoft.AspNetCore.Http (NuGet) Vendor— Affected before 2.1.22 Fixed in 2.1.22 Patch available GHSA-hxrm-9w7p-39cc
  • Microsoft.AspNetCore.App (NuGet) Vendor— Affected before 2.1.22 Fixed in 2.1.22 Patch available GHSA-hxrm-9w7p-39cc
  • Microsoft.Owin (NuGet) Vendor— Affected before 4.1.1 Fixed in 4.1.1 Patch available GHSA-hxrm-9w7p-39cc
  • Microsoft.AspNetCore.App.Runtime.linux-arm (NuGet) Vendor— Affected 3.1.0 to before 3.1.8 Fixed in 3.1.8 Patch available GHSA-hxrm-9w7p-39cc
  • Microsoft.AspNetCore.App.Runtime.linux-arm64 (NuGet) Vendor— Affected 3.1.0 to before 3.1.8 Fixed in 3.1.8 Patch available GHSA-hxrm-9w7p-39cc
  • Microsoft.AspNetCore.App.Runtime.linux-musl-x64 (NuGet) Vendor— Affected 3.1.0 to before 3.1.8 Fixed in 3.1.8 Patch available GHSA-hxrm-9w7p-39cc
  • Microsoft.AspNetCore.App.Runtime.linux-x64 (NuGet) Vendor— Affected 3.1.0 to before 3.1.8 Fixed in 3.1.8 Patch available GHSA-hxrm-9w7p-39cc
  • Microsoft.AspNetCore.App.Runtime.osx-x64 (NuGet) Vendor— Affected 3.1.0 to before 3.1.8 Fixed in 3.1.8 Patch available GHSA-hxrm-9w7p-39cc
  • Microsoft.AspNetCore.App.Runtime.win-arm (NuGet) Vendor— Affected 3.1.0 to before 3.1.8 Fixed in 3.1.8 Patch available GHSA-hxrm-9w7p-39cc
  • Microsoft.AspNetCore.App.Runtime.win-x64 (NuGet) Vendor— Affected 3.1.0 to before 3.1.8 Fixed in 3.1.8 Patch available GHSA-hxrm-9w7p-39cc
  • Microsoft.AspNetCore.App.Runtime.win-x86 (NuGet) Vendor— Affected 3.1.0 to before 3.1.8 Fixed in 3.1.8 Patch available GHSA-hxrm-9w7p-39cc
  • Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 (NuGet) Vendor— Affected 3.1.0 to before 3.1.8 Fixed in 3.1.8 Patch available GHSA-hxrm-9w7p-39cc
  • Microsoft.AspNetCore.App.Runtime.win-arm64 (NuGet) Vendor— Affected 3.1.5 to before 3.1.8 Fixed in 3.1.8 Patch available GHSA-hxrm-9w7p-39cc

CPE configurations NVD · 13

CPEVersionsRoleVendor
cpe:2.3:a:microsoft:asp.net_core:*:*:*:*:*:*:*:*2.1 – 2.1.21; 3.1 to before 3.1.8VulnerableMicrosoft
cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*32VulnerableFedoraproject
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*33VulnerableFedoraproject
cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*8.0VulnerableRed Hat
cpe:2.3:o:redhat:enterprise_linux_aus:8.2:*:*:*:*:*:*:*8.2VulnerableRed Hat
cpe:2.3:o:redhat:enterprise_linux_aus:8.4:*:*:*:*:*:*:*8.4VulnerableRed Hat
cpe:2.3:o:redhat:enterprise_linux_aus:8.6:*:*:*:*:*:*:*8.6VulnerableRed Hat
cpe:2.3:o:redhat:enterprise_linux_eus:8.2:*:*:*:*:*:*:*8.2VulnerableRed Hat
cpe:2.3:o:redhat:enterprise_linux_eus:8.4:*:*:*:*:*:*:*8.4VulnerableRed Hat
cpe:2.3:o:redhat:enterprise_linux_eus:8.6:*:*:*:*:*:*:*8.6VulnerableRed Hat
  • cpe:2.3:a:microsoft:asp.net_core:*:*:*:*:*:*:*:* Versions 2.1 – 2.1.21; 3.1 to before 3.1.8 Vulnerable ·Microsoft
  • cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:* Versions 32 Vulnerable ·Fedoraproject
  • cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* Versions 33 Vulnerable ·Fedoraproject
  • cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:* Versions 8.0 Vulnerable ·Red Hat
  • cpe:2.3:o:redhat:enterprise_linux_aus:8.2:*:*:*:*:*:*:* Versions 8.2 Vulnerable ·Red Hat
  • cpe:2.3:o:redhat:enterprise_linux_aus:8.4:*:*:*:*:*:*:* Versions 8.4 Vulnerable ·Red Hat
  • cpe:2.3:o:redhat:enterprise_linux_aus:8.6:*:*:*:*:*:*:* Versions 8.6 Vulnerable ·Red Hat
  • cpe:2.3:o:redhat:enterprise_linux_eus:8.2:*:*:*:*:*:*:* Versions 8.2 Vulnerable ·Red Hat
  • cpe:2.3:o:redhat:enterprise_linux_eus:8.4:*:*:*:*:*:*:* Versions 8.4 Vulnerable ·Red Hat
  • cpe:2.3:o:redhat:enterprise_linux_eus:8.6:*:*:*:*:*:*:* Versions 8.6 Vulnerable ·Red Hat
Show 3 more CPE
CPEVersionsRoleVendor
cpe:2.3:o:redhat:enterprise_linux_tus:8.2:*:*:*:*:*:*:*8.2VulnerableRed Hat
cpe:2.3:o:redhat:enterprise_linux_tus:8.4:*:*:*:*:*:*:*8.4VulnerableRed Hat
cpe:2.3:o:redhat:enterprise_linux_tus:8.6:*:*:*:*:*:*:*8.6VulnerableRed Hat
  • cpe:2.3:o:redhat:enterprise_linux_tus:8.2:*:*:*:*:*:*:* Versions 8.2 Vulnerable ·Red Hat
  • cpe:2.3:o:redhat:enterprise_linux_tus:8.4:*:*:*:*:*:*:* Versions 8.4 Vulnerable ·Red Hat
  • cpe:2.3:o:redhat:enterprise_linux_tus:8.6:*:*:*:*:*:*:* Versions 8.6 Vulnerable ·Red Hat

Remediation

  • Fix · CNA ASP.NET Core 2.1 (Microsoft) Fixed in publication
  • Fix · CNA ASP.NET Core 3.1 (Microsoft) Fixed in publication
  • Fix · GHSA-hxrm-9w7p-39cc Microsoft.AspNetCore.Http (NuGet) Fixed in 2.1.22 Advisory →
  • Fix · GHSA-hxrm-9w7p-39cc Microsoft.AspNetCore.App (NuGet) Fixed in 2.1.22 Advisory →
  • Fix · GHSA-hxrm-9w7p-39cc Microsoft.Owin (NuGet) Fixed in 4.1.1 Advisory →
  • Fix · GHSA-hxrm-9w7p-39cc Microsoft.AspNetCore.App.Runtime.linux-arm (NuGet) Fixed in 3.1.8 Advisory →
  • Fix · GHSA-hxrm-9w7p-39cc Microsoft.AspNetCore.App.Runtime.linux-arm64 (NuGet) Fixed in 3.1.8 Advisory →
  • Fix · GHSA-hxrm-9w7p-39cc Microsoft.AspNetCore.App.Runtime.linux-musl-x64 (NuGet) Fixed in 3.1.8 Advisory →
  • Fix · GHSA-hxrm-9w7p-39cc Microsoft.AspNetCore.App.Runtime.linux-x64 (NuGet) Fixed in 3.1.8 Advisory →
  • Fix · GHSA-hxrm-9w7p-39cc Microsoft.AspNetCore.App.Runtime.osx-x64 (NuGet) Fixed in 3.1.8 Advisory →
  • Fix · GHSA-hxrm-9w7p-39cc Microsoft.AspNetCore.App.Runtime.win-arm (NuGet) Fixed in 3.1.8 Advisory →
  • Fix · GHSA-hxrm-9w7p-39cc Microsoft.AspNetCore.App.Runtime.win-x64 (NuGet) Fixed in 3.1.8 Advisory →
  • Fix · GHSA-hxrm-9w7p-39cc Microsoft.AspNetCore.App.Runtime.win-x86 (NuGet) Fixed in 3.1.8 Advisory →
  • Fix · GHSA-hxrm-9w7p-39cc Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 (NuGet) Fixed in 3.1.8 Advisory →
  • Fix · GHSA-hxrm-9w7p-39cc Microsoft.AspNetCore.App.Runtime.win-arm64 (NuGet) Fixed in 3.1.8 Advisory →

Red Hat 2 advisories

  • RHSA-2020:3699 Released 2020-09-08 · Red Hat rating Important
    .NET Core 3.1 security and bugfix update
    • Red Hat Enterprise Linux AppStream (v. 8) aspnetcore-runtime-3.1-3.1.8-2.el8_2, aspnetcore-targeting-pack-3.1-3.1.8-2.el8_2, dotnet-3.1.108-2.el8_2 +9
  • RHSA-2020:3697 Released 2020-09-08 · Red Hat rating Important
    .NET Core 3.1 security and bugfix update for Red Hat Enterprise Linux
    • .NET Core on Red Hat Enterprise Linux ComputeNode (v. 7) rh-dotnet31-aspnetcore-runtime-3.1-3.1.8-1.el7, rh-dotnet31-aspnetcore-targeting-pack-3.1-3.1.8-1.el7, rh-dotnet31-dotnet-3.1.108-1.el7 +8
    • .NET Core on Red Hat Enterprise Linux Server (v. 7) rh-dotnet31-aspnetcore-runtime-3.1-3.1.8-1.el7, rh-dotnet31-aspnetcore-targeting-pack-3.1-3.1.8-1.el7, rh-dotnet31-dotnet-3.1.108-1.el7 +8
    • .NET Core on Red Hat Enterprise Linux Workstation (v. 7) rh-dotnet31-aspnetcore-runtime-3.1-3.1.8-1.el7, rh-dotnet31-aspnetcore-targeting-pack-3.1-3.1.8-1.el7, rh-dotnet31-dotnet-3.1.108-1.el7 +8

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
.NET Core on Red Hat Enterprise Linux ComputeNode (v. 7)Fixed RHSA-2020:3697
.NET Core on Red Hat Enterprise Linux Server (v. 7)Fixed RHSA-2020:3697
.NET Core on Red Hat Enterprise Linux Workstation (v. 7)Fixed RHSA-2020:3697
Red Hat Enterprise Linux AppStream (v. 8)Fixed RHSA-2020:3699
Not affected: 2 products
  • .NET Core 2.1 on Red Hat Enterprise Linux
  • Red Hat Enterprise Linux 8

Timeline

  1. 2026-10-02 Threatist record created from CVE-2020-1045
  2. 2026-10-03 Alias added: GHSA-hxrm-9w7p-39cc

References

Patch 1

Advisory 5

Other 9

  • TI-2023-23979 The HTTP/2 protocol allows a denial of service (server resource consumption) because… KEVCVSS 3.1HIGH 7.5
  • TI-2023-19596 .NET and Visual Studio Denial of Service Vulnerability KEVCVSS 3.1HIGH 7.5
  • TI-2025-34970 ASP.NET Security Feature Bypass Vulnerability CVSS 3.1CRITICAL 9.9
  • TI-2024-14164 .NET Denial of Service Vulnerability CVSS 3.1HIGH 7.5
  • TI-2023-18092 ASP.NET Core Denial of Service Vulnerability CVSS 3.1HIGH 8.2
  • TI-2023-18392 ASP.NET Core Security Feature Bypass Vulnerability CVSS 3.1MEDIUM 6.2
See all 40 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences