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>
Metrics
CVSS 3.1 7.5/10
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:NAffected software
| Vendor | Product | Versions |
|---|---|---|
| Microsoft | ASP.NET Core 2.1 | >= 2.0, < publication |
| Microsoft | ASP.NET Core 3.1 | >= 3.0, < publication |
References
- https://access.redhat.com/errata/RHSA-2020:3699Third Party Advisory
- https://github.com/dotnet/core/blob/main/release-notes/3.1/3.1.8/3.1.8.md#changes-in-318Release Notes, Third Party Advisory
- 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://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1045Patch, Vendor Advisory
- https://security.snyk.io/vuln/SNYK-RHEL8-DOTNET-1439600Third Party Advisory
- https://access.redhat.com/errata/RHSA-2020:3699Third Party Advisory
- https://github.com/dotnet/core/blob/main/release-notes/3.1/3.1.8/3.1.8.md#changes-in-318Release Notes, Third Party Advisory
- 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://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1045Patch, Vendor Advisory
- https://security.snyk.io/vuln/SNYK-RHEL8-DOTNET-1439600Third Party Advisory
Timeline
- Published
- Sep 11, 2020
- Last modified
- Jun 17, 2026
- NVD status
- Modified