Cookie parsing failure
A security feature bypass vulnerability exists in the way Microsoft ASP.NET Core parses encoded cookie names.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.The security update addresses the vulnerability by fixing the way the ASP.NET Core cookie parser handles encoded names., aka 'Microsoft ASP.NET Core Security Feature Bypass Vulnerability'.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| .NET (NuGet) | Microsoft.AspNetCore.App | < 2.1.22 | 2.1.22 |
| .NET (NuGet) | Microsoft.AspNetCore.App.Runtime.linux-arm | >= 3.1.0, < 3.1.8 | 3.1.8 |
| .NET (NuGet) | Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 3.1.0, < 3.1.8 | 3.1.8 |
| .NET (NuGet) | Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 3.1.0, < 3.1.8 | 3.1.8 |
| .NET (NuGet) | Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 3.1.0, < 3.1.8 | 3.1.8 |
| .NET (NuGet) | Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 3.1.0, < 3.1.8 | 3.1.8 |
| .NET (NuGet) | Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 3.1.0, < 3.1.8 | 3.1.8 |
| .NET (NuGet) | Microsoft.AspNetCore.App.Runtime.win-arm | >= 3.1.0, < 3.1.8 | 3.1.8 |
| .NET (NuGet) | Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 3.1.5, < 3.1.8 | 3.1.8 |
| .NET (NuGet) | Microsoft.AspNetCore.App.Runtime.win-x64 | >= 3.1.0, < 3.1.8 | 3.1.8 |
| .NET (NuGet) | Microsoft.AspNetCore.App.Runtime.win-x86 | >= 3.1.0, < 3.1.8 | 3.1.8 |
| .NET (NuGet) | Microsoft.AspNetCore.Http | < 2.1.22 | 2.1.22 |
| .NET (NuGet) | Microsoft.Owin | < 4.1.1 | 4.1.1 |
References
- https://nvd.nist.gov/vuln/detail/CVE-2020-1045
- https://github.com/dotnet/announcements/issues/165
- https://github.com/dotnet/aspnetcore/issues/25701
- https://github.com/dotnet/aspnetcore/issues/25701#issuecomment-689434477
- https://github.com/github/advisory-database/issues/302
- https://github.com/dotnet/aspnetcore/pull/24264
- https://access.redhat.com/errata/RHSA-2020:3699
- https://github.com/dotnet/core/blob/main/release-notes/3.1/3.1.8/3.1.8.md#changes-in-318
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5LN2FUVBSVPGK7AU3NMLO3YR6CGONQPB
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ASICXQXS4M7MTAF6SGQMCLCA63DLCUT3
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/5LN2FUVBSVPGK7AU3NMLO3YR6CGONQPB
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ASICXQXS4M7MTAF6SGQMCLCA63DLCUT3
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1045
- https://security.snyk.io/vuln/SNYK-RHEL8-DOTNET-1439600
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N- Weakness (CWE)
-- Platform
- .NET (NuGet)
- Package
Microsoft.AspNetCore.App, Microsoft.AspNetCore.App.Runtime.linux-arm, Microsoft.AspNetCore.App.Runtime.linux-arm64- Disclosed
- 24.05.2022
- Updated
- 11.10.2026 11:23
Sources and licenses
OSV / GitHub Advisory Database - GHSA-hxrm-9w7p-39cc - CC BY 4.0
Vulnerability history: Microsoft.AspNetCore.App
All published vulnerabilities of this package (.NET (NuGet)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 8
- First → latest
- 10.2018 05.2022
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 5
- Medium 3
Disclosures per year
- 2018: 2
- 2019: 0
- 2020: 0
- 2021: 0
- 2022: 6
- 2023: 0
- 2024: 0
- 2025: 0
- 2026: 0
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Cookie parsing failure this entry
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