Vulnerability · Published Sep 11, 2020 · Assigned by microsoft
CVE-2020-1045Microsoft ASP.NET Core Security Feature Bypass Vulnerability
High 7.5
In plain English
A high-severity security flaw in ASP.NET Core 2.1 from Microsoft. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 5.9% (higher than 93% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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>
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| NuGet | microsoft.aspnetcore.app | 2.1.22 | GHSA-hxrm-9w7p-39cc |
| NuGet | microsoft.aspnetcore.app.runtime.linux-arm | 3.1.8 | GHSA-hxrm-9w7p-39cc |
| NuGet | microsoft.aspnetcore.app.runtime.linux-arm64 | 3.1.8 | GHSA-hxrm-9w7p-39cc |
| NuGet | microsoft.aspnetcore.app.runtime.linux-musl-arm64 | 3.1.8 | GHSA-hxrm-9w7p-39cc |
| NuGet | microsoft.aspnetcore.app.runtime.linux-musl-x64 | 3.1.8 | GHSA-hxrm-9w7p-39cc |
| NuGet | microsoft.aspnetcore.app.runtime.linux-x64 | 3.1.8 | GHSA-hxrm-9w7p-39cc |
| NuGet | microsoft.aspnetcore.app.runtime.osx-x64 | 3.1.8 | GHSA-hxrm-9w7p-39cc |
| NuGet | microsoft.aspnetcore.app.runtime.win-arm | 3.1.8 | GHSA-hxrm-9w7p-39cc |
| NuGet | microsoft.aspnetcore.app.runtime.win-arm64 | 3.1.8 | GHSA-hxrm-9w7p-39cc |
| NuGet | microsoft.aspnetcore.app.runtime.win-x64 | 3.1.8 | GHSA-hxrm-9w7p-39cc |
| NuGet | microsoft.aspnetcore.app.runtime.win-x86 | 3.1.8 | GHSA-hxrm-9w7p-39cc |
| NuGet | microsoft.aspnetcore.http | 2.1.22 | GHSA-hxrm-9w7p-39cc |
| NuGet | microsoft.owin | 4.1.1 | GHSA-hxrm-9w7p-39cc |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Microsoft | ASP.NET Core 2.1 | 2.0 – before publication |
| Microsoft | ASP.NET Core 3.1 | 3.0 – before publication |
References
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1045
- FEDORA-2020-e2deb72e0f vendor-advisory
- FEDORA-2020-48fa1ad65c vendor-advisory
- https://github.com/dotnet/core/blob/main/release-notes/3.1/3.1.8/3.1.8.md#changes-in-318
- https://security.snyk.io/vuln/SNYK-RHEL8-DOTNET-1439600
- https://access.redhat.com/errata/RHSA-2020:3699