# CVE-2020-1045: Microsoft ASP.NET Core Security Feature Bypass Vulnerability

CVE-2020-1045 is fixed in 11 products on 1 platform, first by RHSA-2020:3699, released September 8, 2020. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2020-1045
- Priority: High
- CVSS: 7.5 (Important)
- EPSS: 0.0593
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Vendor exploitability assessment: Exploitation Less Likely
- Published: Sep 8, 2020
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2020-1045

## Description

<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>

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | aspnetcore-runtime-3.1 RHEL 8 | 0:3.1.8-2.el8_2 | [RHSA-2020:3699](https://patchblox.com/security/data/fix/linux/rhsa-2020-3699.md) | Sep 8, 2020 |
| Linux | aspnetcore-runtime-3.1 ol 8 | 0:3.1.8-2.0.1.el8_2 | [ELSA-2020-3699](https://patchblox.com/security/data/fix/linux/elsa-2020-3699.md) | Sep 11, 2020 |
| Linux | aspnetcore-targeting-pack-3.1 RHEL 8 | 0:3.1.8-2.el8_2 | [RHSA-2020:3699](https://patchblox.com/security/data/fix/linux/rhsa-2020-3699.md) | Sep 8, 2020 |
| Linux | aspnetcore-targeting-pack-3.1 ol 8 | 0:3.1.8-2.0.1.el8_2 | [ELSA-2020-3699](https://patchblox.com/security/data/fix/linux/elsa-2020-3699.md) | Sep 11, 2020 |
| Linux | dotnet RHEL 8 | 0:3.1.108-2.el8_2 | [RHSA-2020:3699](https://patchblox.com/security/data/fix/linux/rhsa-2020-3699.md) | Sep 8, 2020 |
| Linux | dotnet ol 8 | 0:3.1.108-2.0.1.el8_2 | [ELSA-2020-3699](https://patchblox.com/security/data/fix/linux/elsa-2020-3699.md) | Sep 11, 2020 |
| Linux | dotnet-apphost-pack-3.1 RHEL 8 | 0:3.1.8-2.el8_2 | [RHSA-2020:3699](https://patchblox.com/security/data/fix/linux/rhsa-2020-3699.md) | Sep 8, 2020 |
| Linux | dotnet-apphost-pack-3.1 ol 8 | 0:3.1.8-2.0.1.el8_2 | [ELSA-2020-3699](https://patchblox.com/security/data/fix/linux/elsa-2020-3699.md) | Sep 11, 2020 |
| Linux | dotnet-host RHEL 8 | 0:3.1.8-2.el8_2 | [RHSA-2020:3699](https://patchblox.com/security/data/fix/linux/rhsa-2020-3699.md) | Sep 8, 2020 |
| Linux | dotnet-host ol 8 | 0:3.1.8-2.0.1.el8_2 | [ELSA-2020-3699](https://patchblox.com/security/data/fix/linux/elsa-2020-3699.md) | Sep 11, 2020 |
| Linux | dotnet-hostfxr-3.1 RHEL 8 | 0:3.1.8-2.el8_2 | [RHSA-2020:3699](https://patchblox.com/security/data/fix/linux/rhsa-2020-3699.md) | Sep 8, 2020 |
| Linux | dotnet-hostfxr-3.1 ol 8 | 0:3.1.8-2.0.1.el8_2 | [ELSA-2020-3699](https://patchblox.com/security/data/fix/linux/elsa-2020-3699.md) | Sep 11, 2020 |
| Linux | dotnet-runtime-3.1 RHEL 8 | 0:3.1.8-2.el8_2 | [RHSA-2020:3699](https://patchblox.com/security/data/fix/linux/rhsa-2020-3699.md) | Sep 8, 2020 |
| Linux | dotnet-runtime-3.1 ol 8 | 0:3.1.8-2.0.1.el8_2 | [ELSA-2020-3699](https://patchblox.com/security/data/fix/linux/elsa-2020-3699.md) | Sep 11, 2020 |
| Linux | dotnet-sdk-3.1 RHEL 8 | 0:3.1.108-2.el8_2 | [RHSA-2020:3699](https://patchblox.com/security/data/fix/linux/rhsa-2020-3699.md) | Sep 8, 2020 |
| Linux | dotnet-sdk-3.1 ol 8 | 0:3.1.108-2.0.1.el8_2 | [ELSA-2020-3699](https://patchblox.com/security/data/fix/linux/elsa-2020-3699.md) | Sep 11, 2020 |
| Linux | dotnet-targeting-pack-3.1 RHEL 8 | 0:3.1.8-2.el8_2 | [RHSA-2020:3699](https://patchblox.com/security/data/fix/linux/rhsa-2020-3699.md) | Sep 8, 2020 |
| Linux | dotnet-targeting-pack-3.1 ol 8 | 0:3.1.8-2.0.1.el8_2 | [ELSA-2020-3699](https://patchblox.com/security/data/fix/linux/elsa-2020-3699.md) | Sep 11, 2020 |
| Linux | dotnet-templates-3.1 RHEL 8 | 0:3.1.108-2.el8_2 | [RHSA-2020:3699](https://patchblox.com/security/data/fix/linux/rhsa-2020-3699.md) | Sep 8, 2020 |
| Linux | dotnet-templates-3.1 ol 8 | 0:3.1.108-2.0.1.el8_2 | [ELSA-2020-3699](https://patchblox.com/security/data/fix/linux/elsa-2020-3699.md) | Sep 11, 2020 |
| Linux | netstandard-targeting-pack-2.1 RHEL 8 | 0:3.1.108-2.el8_2 | [RHSA-2020:3699](https://patchblox.com/security/data/fix/linux/rhsa-2020-3699.md) | Sep 8, 2020 |
| Linux | netstandard-targeting-pack-2.1 ol 8 | 0:3.1.108-2.0.1.el8_2 | [ELSA-2020-3699](https://patchblox.com/security/data/fix/linux/elsa-2020-3699.md) | Sep 11, 2020 |

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